Trust me. I sucked MAJORLY, and give it a week you will be laughing at how bad you were against Bots.
I found the champ I liked very fast (Akali) and well, destroyed from then on.
Tips: Find a champ you semi-like, google for a good item build, in AI games, bots don't follow you into bushes so use those often, don't forget to run about the sections of the map killing the special mobs (this is called jungle) for blue / red buff's, gold, exp, etc.
Oh and don't get discouraged if you are put with a retard in your lane, difficult I know but, best to just let him troll and try to mop up any kills lol.
Add me if you want, I can help if need be: Koriban22