Write big and legible. You have to be able to read what you've written with just a glance. Use color to highlight or add notes on important details you want to be sure to tell the class. Work out a standard system to make it easier to look at your own notes with just a glance. Problem number in upper right hand corner.
Figure takes up top left of page.
Values and formulas given in the problem take up top right of page. Short description of the problem under the figure. Give yourself a short description of what each part of the problem is asking for so you don't simply have a page full of answers. Work out an Outline for the Discussion You want to organize the discussion in your head at the minimum. Preferably, make a small outline that you can leave sitting on the table or desk by the blackboard.