As Shaco, Kassadin, or anyone with Flash, you can teleport farther than the range the spell actually indicates, here is how:
As Shaco for example (short range teleport, deceive): Stand away from a tree line but with just a sliver of your spell range indicator inside the trees, then click in the direction of the trees but within the spell range and you will teleport all the way to the other side of the trees! Even if its double your true range. I have never gotten stuck in the trees and I think this occurs exactly so you cannot get stuck so use it to your advantage to get away from ganks!
Using heal: if you use heal early game when you're safe and sound, just to heal hp, it's usually a bad move. Early game you should have a hp regen item, pots, lifesteal or champion spells for that use. Summoner Heal early game is best used to trick your enemy into thinking he can kill you and using it at the last minute to kill him.
Of course, in order to pull this off efficiently you need to pay attention to which enemies picked heal and which already used it recently. Or else your plan may backfire ^^