Don't listen to tom. He hates because he doesn't know how to roll. What area are you in? Some good stepping stones might be (in no particular order) shoshone, poudre narrows, gore, numbers/fractions/pine creek, clear creek. Some of those are a lot harder than others, and of course you don't want to do any of them alone. Your best bet is to just make friends with a sick boater and get them to guide you down some stuff.
Also, once your local run gets too easy, invent more difficult moves to challenge yourself. Your best preparation is probably playboating, though. The main reason tom is so bad at kayaking is because he never playboats.