Know when to roam. Enemy laners dead? Feel free to drop a ward or two and gank mid.
Try to leave health packs for people other then your ADC
Starting with W when you have a low sustain jungler, throwing down 3 packs, recalling and going back to lane(/leash depending on where your jungler is starting) will make your jungler love you forever and give them a much better start
Your stun range increases slightly after hitting it's first unit, because of that you can stun people at the very edge of your range as long as they're touching something with their butt
Ulting the entire enemy team generally won't do much (Unless some allies can get in range for their combos during the stasis, then that could be good) but ulting their entire front line can make your assassin very very VERY happy. And also get them a triple kill. Maybe.
If you (And any allies) are running through the jungle to escape enemies and there is a fork in the road, use your Magical Journey on the path's wall that you're NOT going down to juke your enemies.
If enemies are coming after you in your Magical Journey they will always have their back to a wall when they come out. So feel free to sun them and make them cry.
People traveling through Magical Journey can still be hit while in it. So if you can't afford to let an enemy come through before stunning him, feel free to use your Q to stun them, because as soon as it hits them in there they'll be stunned (Since they're in a wall).
That's all for now folks.