noodling/commenting.txt

basics of this: explain high level goal of each logically seperate chunk of code or algorithm. Explain any confusing syntax. Explain use of unusual libraries. Try to list any assumptions that might be incorrect.
if a variable or function's purpose isn't self explanitory, note what it is for in a comment.
At the start of any (substantial) program, note what it is for and how to make it run. Also who wrote it, license, etc.