You should always start the game with a tear. Ask a teammate to stay in base with you until 0:55 so that you can put Q's on their head and stack up that tear to around 30 stacks.

Your bread and butter combo is QWQE. Later in the game this will mean perma stuns and slows on the enemy.

Another variant is EQWQ. The slow makes it easier to land your bombs.

Once you have your Liandry's, you should start to dish out some decent damage. Afer 3 items you will become mad annoying due to the low CD reduction.

Your late R cooldown period should be anywhere around 25 seconds. Which means, you might be able to use your R twice in a teamfight.

Positioning is key, you're rarely in the forefront of a teamfight. If you do get caught, it's easier to land 2 Q's on yourself for the stun, and then run away with your E.

Using E on your enemy, when ganked for example, is more valuable than using E on yourself. It's a pretty strong slow.