Don't intermix these types of comments. Use helper functions is a matter of taste. As a rule of thumb, a Scheme function shouldn't be more than ten lines or so of code, and will usually be five to six lines of code. Later in the semester it includes using structures as needed. Overall, this point is not a big issue in Scheme.
Magic numbers are constants hard-wired in the code that occur more than once.
All others should be given a name. Note that this means toString or paramString is one of the first methods you write for a class, so that you can print out debugging versions of your object. Documentation You should contain the following information with your programs. What files contain the user documentation and the code-architecture information. You can presume that the reader is familiar with the assignment handout, but not discussions from class.