i have to ask. whats the difference between a silver maokai/renekton and a diamond one?
There are a million things to concentrate on in LoL.
Better players are better at doing more of those than worse players.
I also feel like you're confusing using 5 abilities well with mastering the millions of things in LoL.
Knowing how a Q works isn't going to help with knowing where the enemy jungler is, how to effectively trade, when to trade, how much you can get away with doing, when to push, when to freeze, how to get amazing CS, resource management, when to back, when to roam, when to team fight, were to pressure other lanes, how to push your advantage, how to recover from a disadvantage...
Silver players have a general idea of these things, but are pretty fuzzy on the specifics.
Diamond players will have a clearer idea of when and how to do many of these things.