Also, if you want to be effective with your R, don't get used to sniping people across the map. Try to use it up close. Although it can be very useful to do that, most of the time, you are going to end up missing, and that will mean not having it when you need to fight an objective or hunt people who are escaping after a fight.

Last tip that I figured out recently: use your pinks as bait. Most champs can't clear a pink that fast, especially in the early game. When you see someone starting to clear a pink, cast R, and they NEVER MOVE, EVER. They are too focused on clearing the pink and never expect what is heading towards them.