Well, you can just check the key bindings to get an idea of what does what. A few of the things that aren't to obvious.
You can use attack move (A) to attack friendly units and try and deny them. You can attack friendly creeps under 50% HP, friendly buildings under 10% HP, and a friendly hero with certain damage over time spells under 10% HP.
Attack move has anther use. You can target any nearby friendly unit to try and make the enemy creeps or tower change targets. If you are getting attacked by a tower, you can use it to make it choose a new target.
The Stop command can also stop channeling spells, like Teleports. If you realize your teleport is just going to kill you, you can stop it.
You can hold down shift to queue up a series of commands. So, you can push it down, tell your guy teleport to a tower, use a dash once the teleport is done, and then use a spell after that, getting things off in very quick succession without having to worry about accidentally canceling something.