Player earns experience doing actions in the game. Not all actions gives point, however. The most common source of points are recipes and missions. Other activities, like fishing in tournaments, can give a point depending of the type of fish you catch.
The amount of points earned also depends on the level of difficult you choose to play the game. In Easy mode, earning points will be always 1. For normal mode, the points are specified by the recipe or action performed.
The player experience is also an independent counter, a global one. You don't earn experience for the skill the action or recipe you did belongs. Instead, you earn points from all sources and, when you reach the next level milestone, you earn a Skill Point. Read the Skills section for more information on how skills works.
The rate of earning points to level up is progressive and based in the classic D&D formula to level up. This means that you will need to earn more and more points to reach the next level, not always the same. The HUD will say your actual Experiences Points and the amount required to reach the next level.