There's already plentiful well-written guides available in the forums (aside from one regarding expeditions...), but I thought I'd take the time to composite them with some focus on money making since I receive a lot of queries about that personally, and aim to give an overarching guide to gameplay since some guides are focused.
One thing a lot of guides miss is what the not self-explanatory values (rep, int) impact, and how best to raise them;
Rep
You get rep from attacking and jobs, but not from expeditions/university/productions running.
Each job gives you a different amount of rep, generally with the robberies the worst and the advanced jobs the best. If you're prioritising rep, it's not that difficult to calculate how much rep/hr each job gives, but if you're lazy I'm sure someone else will have the numbers to spare. Prestiging jobs for time 5 times can also double the rep you get per hour.
Attacking is by far the more significant way of gaining rep, as SAGE has perfectly demonstrated, converting almost 60 attacks into thousands of rep daily.
Mugging and hospitalising give you less rep than just a normal attack.
Rep per attack depends on FFM (fair fight modifer), and the opponent's level (not yours). FFM maxes at 3 and depends on how similar your gym stats are to theirs. The opponent's level increases rep gain exponentially, so while level 1 targets can give ~46-49 rep (3x FFM), level 40+ targets can give 300+ rep (or even 400+).
Therefore, if you were to choose to dump thousands of energy into attacks, it'd net you more rep if you chose to do it after grinding your gym stats first -- with higher stats, you can take on higher level targets. For example, the strongest player in the game right now could theoretically gain over 25,000 rep per day right now if they wanted to. If you're weak, there's a couple inactive high-level targets floating around, most notable being PIRATEONI (lvl 19, ~16K stats) and _ACE (lvl 20, ~80K stats?).
As proof, MAZULIS does less attacks per day than SAGE, but is gaining rep much faster -- focused on stats first, to get better targets.
INT
As the other guides outline, INT is arguably the most important value to max out as soon as you can.
INT impacts job success rate (slightly), and gym gains.
Due to its massive (and I mean massive) impact on gym gains, it's no surprise everyone recommends you max out the value before honing in on your gym gains.
JARI's guide is decent when it comes to explaining how to max this value, but essentially the uni course order to max your INT quickly is MED1000, MED1030, MED1050, BM1000, MED1080, MED1020, then the last 3 MED.
People often recommend waiting until your INT reaches 70-75 before dumping all your energy into the university, but this value is arbitrary. In truth, the fastest way to reach max INT is to start dumping energy immediately. So really it's a balance of gaining some rep in the meantime, and ensuring you have the money to afford 8 coke & energy-refill each day, before you start the grind. Purposefully waiting until 70 INT if you're rich enough is not worth it, and will only slow your progression through the game.
Also, one of the missions gives you 10 INT, so don't forget to do those.
If you're interested in the maths, INT growth is quadratic, not exponential like other people claim.
Some properties increase the INT cap, with the museum upgrade. Although not mentioned in guides, most people recommend getting a Town House (+100 INT), then a Private Estate (+200 INT).
Education courses can be completed faster with other property upgrades, but these are hugely expensive for minimal reduction. Even I didn't waste my money on those for a long time.
That aside, here's some other strategies I hadn't yet seen mentioned in guides
Money making
Making money is (until the late-stage game) a very important aspect of the game, and probably what I am the most qualified to talk about.
Easily the best way to make money is through jobs. Again you can calculate it yourself or ask around, but the most profitable jobs currently are farm robbery and construction robbery.
On the topic of jobs, a lot of people mention going to 5% in intimidation then switching to robbery, but again that 5% statistic is a completely arbitrary guess -- I challenge anyone to actually provide any reasoning for it.
Despite taking forever, the two advanced jobs give pretty minimal money per hour in comparison, so are only worth doing overnight.
Prestiging is a pretty simple matter; if you plan to prestige the job roughly 7 times or more, doing all 5 time-prestiges before reward-prestiges is the way to go. If it's a long job like construction robbery and you plan to only prestige it a couple times, prestiging for reward will give you more profit overall.
If you're choosing to do farm robbery, set an alarm on your phone. Life is too busy to remember to check your phone every 7.5 minutes (once fully prestiged). As someone who's farmed likely over a hundred thousand bags of fert, this is necessary, along with having a lifestyle which allows for this. If you're often busy at work, money making is going to be more difficult for you.
In terms of productions, coke production gives by far the most daily profit -- the others don't even come close in comparison. Coke production should also be bought as soon as you can, so you don't have to rely on the market/traders. Alcohol and fert production change in profit very often, but usually give roughly the same profit per production.
Mugging random people is probably the worst way to make money, and the worst use of your energy. Being poor is not a reason to mug people - you'll remain poor if you waste your energy doing it. Unless you buymug, the chances of finding someone who's left cash on hand is very low, so you're just passing up the opportunity for more rep in return for like £10K sometimes.
If you're like me, you could always create a script too. Although the script contributed to less than 20% of my networth, it's still a pretty fun endeavour. Less boring than pressing the job button every now and then.
If you're like IEJEN, you can refer every man and their dog to Cartel Empire and get a lot of rewards every 10 levels.
If you're like FAMINE, you can show your support to Diablo by purchasing hundreds of pounds worth of donator packs, and skyrocket to £1B networth before I could make it there :))
Be aggressive with your trading, particularly with agave/paste. Mostly everyone knows fert is still overvalued, but there's no reason you should be listing agave on the market for a £1K+ discount. Try not to feel bad about undercutting people or being undercut yourself, since everyone does it.
If you have spare time, check the market. Often people undercut by preposterous amounts, or mysteriously ignore the 10%-warning.
If you're a buyer, finding a trader helps. As a seller, scoping out a buyer is pretty fruitless, unless they're too clueless to watch the market -- if prices drop, they'll flock elsewhere.
Last but not least, spin the wheel twice every day. It has been nerfed, but is still very profitable on average.
Personally I'd ignore the scoreboard if you're trying to track your networth growth -- it values items poorly and completely ignores the cost of production buildings. My networth has supposedly dropped over £200M in a day from buying things.
Gaining energy
I've already written a bit about spending energy (building stats initially, gaining some rep, maxxing INT when you're rich enough, then returning to building stats/rep), but haven't discussed getting energy.
As you probably already know, you can take 8 cocaine per day (currently that's ~£2.7M, although prices are unstable currently (mid-June) due to the recent production nerf).
Point refills set your energy to the max, and currently cost ~£1M. If you're a subscriber/have used a donator pack, your max energy is 200, meaning point refills give you double the energy if you're on donator status. Therefore you likely want to be using a donator pack (DP) every month (~£6M on market, very variable), but if for some reason you can't, point refills still give a comparable energy/£ to using coke.
Using these 3 methods (8 coke, refill, DP) that's £3.89M per day, if you can't supply any of it yourself. I decided to show this calculation here, since no other guides do it, despite boosting your energy being the best use of money in the whole game. This (£3.89M/day) is quite expensive, but is attainable even by the new player after some time, with enough dedication to constantly doing well-paying jobs.
And of course it's pretty self-evident that producing your own coke is worth it without doubt. At 160K rep you unlock the first coke factory, and at 640K you get the fourth, which finally gives you enough coke daily with ~0.75 extra (not accounting for Perks). Going from 0 to 640K rep certainly takes a while, but I've mentioned the 2 strategies previously.
Alcohol is the final way to gain energy, and is probably worth using if you don't plan on selling it. Otherwise, it'll just accumulate in your inventory over time, like it did for me. I currently have over 700 bottles and am slowly chipping away at them. The top rep players are currently at the point where they could produce 12+ alcohol per day on average, if they chose to buy all productions.
Buy productions?
If coke: yes, 100%. You should save up money so that you can buy it immediately as soon as you unlock a new one.
Fert productions give pretty decent profit, but the price rises very sharply, and to buy the last one (20th) it'd take almost 100 days to pay itself off. My personal advice is to buy them both until it becomes unreasonably expensive. Fert productions are good in particular, since they convert production materials (fert) into cannabis, which is directly sellable to the drug den, sometimes for over £27K each. Hence, it's an easy way to reliably and effortlessly convert items into cash, with no fear of being mugged.
Alcohol stills are currently quite profitable (even more-so than cocaine factories), but only if you manage to sell the alcohol. But this profit margin may be due to the new event driving prices up.
Doctors offices provide you your own meds, but profit-wise are very lame. If you're in a good cartel (i.e. Abusement Park :D), meds will often be amicably provided for younger players who haven't unlocked productions yet. On the topic of meds, never buy from the market, I see so many new accounts purchasing meds from there, unaware that they are ubiquitously cheaper in the pharmacy.
Very vague expeditions guide
I don't have too much to say about expeditions since I'm not all that far through it, and someone will eventually write a complete guide on it, but for now I'll just say what's been working for me and others.
It starts of pretty similar to farming jobs all day with the low expedition time, but pretty quickly you can get to higher regions with expedition times 5 hours or more.
In terms of sicarios, what I did along with a couple others was to recruit sicarios along the way, until you reach Potosi/Santa Cruz, then swap them out to have at least 3 times. This will allow you to have a pretty decent success rate for Beni/Cochabamba/Ororu, which take a fairly decent amount of time, so you don't need to be checking it often.
Gear-wise, Glock 18s and Kevlar Weave Vest are decent choices, tacking an extra ~£650K per sicario.
Expeditions are very expensively initially, but will pay themselves back eventually.
If you're curious, when you unlock the final region (which I think nobody has yet), to get 3 full teams of max weapons/armour, it'd cost ~£394M (plus sicario hiring cost), potentially the largest investment in the game, maybe only rivalled by a Private Estate.
Also, note that the expeditions-XP ("effort"/"notoriety") per region on the wiki is incorrect, Diablo's mentioned the proper values somewhere in the Discord.
(This is going to make some people annoyed haha :P )
That was a bit of a mess, far less structured than most other guides, but hopefully it answered some queries you might've had particularly about the best way to do things.
There's already plentiful well-written guides available in the forums (aside from one regarding expeditions...), but I thought I'd take the time to composite them with some focus on money making since I receive a lot of queries about that personally, and aim to give an overarching guide to gameplay since some guides are focused.
One thing a lot of guides miss is what the not self-explanatory values (rep, int) impact, and how best to raise them;
Rep
INT
That aside, here's some other strategies I hadn't yet seen mentioned in guides
Money making
Gaining energy
Buy productions?
Very vague expeditions guide
Cartel guide
That was a bit of a mess, far less structured than most other guides, but hopefully it answered some queries you might've had particularly about the best way to do things.