Draw constrained to angle
Sometimes you'll want to draw a line at a specific angle, and it is surprising how many people do it the long way by drawing the line, and then rotating it.
So, if this is you, you're in luck as you're about to be amazed!
Whenever you want to constrain drawing to a particular angle, press the less than key (<) followed by the angle that you want to use. Then, you can pick anywhere on screen, and the line will be drawn at the angle specified. Of course for commands such as LINE you'll have to pick a basepoint first.
So, I hope this helps someone - its really handy to know sometimes!