Alright. I suggest finding a friend and playing a custom game. Play top lane only.. see who is better in the top lane only game. (if you need a friend feel free to add me iittala, thats double i double t ala.)
The better player can only go top lane. The other player gets a "buff" (an expcetion) so maybe they get a bot added to their tream.. or maybe they can farm any lane they want to at any point. The better player says every time he backs, the better player "says" on a call everything he does before he does it. The less skilled player picks the other players champion.
when the less skilled player wins the game, take away the advantage. see if they can win the game again. Keep removing advantages until there are none and see if they can win. it sounds strange.. but having small advantages helps you realize what you weren`t doing. by seeing what your not doing you can improve upon it.
and yes bots are great to practice with.. I became a very strong support player from playing a game of feed the cho-gath. you have 8 players and a cho gath bot on each team. The goal of the game is to have the cho-gath with the best score. The most direct way to do this is by playing a support.. another option is to play an assassin and see if you can keep killing cho-gath. Cho gath death is one of the worst sounds in the game. And cho gath feasts himself larger the longer you can keep him alive creating a reward mechanic for him not dying.