These are some guidelines you may wish to follow to better your league career. I myself live by these guidelines.
During the lane phase. If you want to be an aggressive asshat make sure your lane partner knows this and is in turn also an aggressive asshat. Nothing is better than communication and execution
If/when there is a Jungler on the enemy team. Try to stay towards the center-close to the wall and brush. this makes it so junglers have to run further towards you. and therefore you are closer to brush and have the ability to come up with a juking plan for maybe 1 or 2 seconds longer.
If there is a mid missing or you somehow manage to notice him/her missing wait until you're in safety to complain to your teammate about his failness. And be polite about it, even if youre seething on the inside, but in way make it seem like you're not a pushover.
If you're pushing a tower. and suddenly you see no enemy on the minimap RUN. Odds are they're going to kill you.
ALWAYS ASSUME YOU'RE NOT SAFE.
Dragon is great kill him often. but don't get into a team fight for it.. Especially if your team started dragon. This can be disregarded if you and your team are total badasses
Ward Baron.
This game has very easy tells for someone focusing you. or trying to harrass you. If they seem to be walking towards you for any reason other than getting minions theyre planning to attack you in some way. You should just run back a smidge and if you time it right. you can get your attack on them instead.
MORE SHALL BE ADDED AS I REMEMBER THEM