1) Show all the steps: do not skip steps or assume that the other part knows what you did, you have to show whay you did.. 2) Justifiy the steps: name the rules or theorems that back up each step; you have to show why you did what you did.. 3) Verify the result: show that the answer is coherent with the information given. I like to add a reflection on the problem: what it shows, what I leaned, how these results help to fix the kwnoledges,etc.