While looking around the announcement thread i found this

• Implemented hidden 'Global Job Experience' which benefits success rate of all Jobs.

Now my question is how do i increase my Global Job Experience Is it from doing jobs? And if so if i failed a jobs does my Global Job Experience decrease?

yes doing jobs increase job experience, no you don't loose exp from fail, but still i would try to avoid fails

diffrent exp for diffrent job, you get more exp for the more difficult ones