When you first start the game, you have no actual abilities but will soon gain access to Smoke powers. While you will gain more abilities as you play through the game, there are also different enhancements you can get to compliment your abilities, such as making some use less of your meter for example.
You can access the skill tree by pressing the Options button and then pressing L2 or R2 until you get to it; press X while on it to get more details. Purchasing new skills and enhancements require you to find Blast Shards, but some of them also require you to be at certain ranks in Good or Evil Karma.
