Quick Level Gain:

If your character is level 5 go to an aria with enemys level 10 save game and kill as many as possible until you get close to leveling save game & exit to main menu & reload game enemies will return kill 2-3 of them to gain level but do not spend attribut points and continue to kill enemies this will level your character up very fast untell you hit level 10 and so on from 10 to 15 / 15 to 20 and so forth. May not work for all versions but it worked on mine.