If you made a mistake assigning your skill or stat points, or you want to try something else - don't worry! You can quickly reset your skills and stats (for one gold) in every village. The challenges in Paw'D do not come from clicking the "correct" abilities in the right order as you level up, but from tough dungeon bosses and trophies. Every choice you make can be undone, so you can always try something else and improve.
If you are just starting out, the earliest way to reset your skills is to talk to Erik in Saliko Village. Resetting your skills will unlearn all your abilities, and return all skill points to you. Similarly, resetting your stats sets them all to 1 again, and returns all stat points to you.
Should you find yourself switching between two or more different sets of abilities a lot, you can obtain the ability to have two or three separate skill sets that you can switch between (while you are out of combat) at the Argan Jungle River. Note, however, that the Jungle River is a level 30 area, so be prepared to fight your way there - or ask a friend to summon you.