What are you building on him, what runes/masteries are you running, and what's your general game plan going in? Like what is the goal on your mind when you start the game?
If they have a weak clear (or if it's basically anyone other than
) i pretty much always go for the level 2 invade. Mastering it isn't too difficult to pull off it's just a matter of timing. Be ready to follow their flash with yours they are always going to panic and try to flash away. It's a good way to jump start your early game and more importantly, set them them behind.
From that point i pretty much live in their jungle, as long as i am keeping tabs on their laners. Generally making the enemy jungler's life a living hell.
If you're having trouble doing this, take a more passive approach. Just power farm like a boss while keeping your eyes on every lane. Do not force a gank. Don't waste your time walking all the way across the map just because the top lane is extended. Prioritize farming over ganking. If you happen to be doing gromp and see that top is overextended then go try that gank.
As for ganking, it's much easier to land your Ult if you walk up behind them. Instead of walking up from the river, take the long way and come in from behind them in the lane. You get the angle much easier that way. Save your W in case they try to flash past you. A neat little trick that i found super useful is to land a point blank Q before you hit R and then you can Q them again while they're flying through the air. It looks super cool and is a great way to easily land your combo.