Here's the official wiki article about character experience. Some nice to know information there about where all those beautiful numbers are coming from.
There is a table that discusses how certain actions(exploring, crafting, killing stuff, events) give you percentile based experience down below. I'll offer some clarification on how the experience is rewarded for crafting since their table isn't 100% clear. Lets assume you're just starting a profession for the first time and you are in the 1 to 100 crafting level. What this table means is for each crafting level you obtain, you gain 1% of the total experience you need to level. When you enter crafting levels between 101 and 200, you are earning 2% experience per crafting level earned and so on. For simplicity sake, below is a list that will help you figure out how many experience levels you can obtain through each crafting tier because math, how does it work!?
Personal Experience Levels gained per Crafting level group
- Crafting Levels 1 - 100: 1 level
- Crafting Levels 101 - 200: 2 levels
- Crafting Levels 201 - 300: 3 levels
- Crafting Levels 301 - 400: 4 levels
If you were curious about some more of the ins and outs of crafting experience and what not, here is the crafting article on the official Guild Wars 2 wiki.