You Level whenever you gain enough experience (xp) for the next level. Every time you gain a level, u get 3 stat points, your energy and stamina gain a few points, and your energy and stamina are fully recharged. You also gain 1 Platinum every 3 Levels.
Generally it can be said that putting all skillpoints into energy and completing quests is the fastest way to gain levels.
|level||total xp needed||xp needed above previous level||max energy increase||max stamina increase||other rewards|