In the main file, you should have a function called either DEMO, TEST, or somesuch name which runs the code through its paces, using dummy data if necessary. If the code is not a complete system or utility, but just a technique, provide comments describing how to use it. If there are auxiliary files that are required, please provide them, or examples of them. There are some examples of common aux files on the BioLisp.org web page. You can refer to those.
Some anal people align their line comments.
Block comments describe what a section of code within a function does. This can also get unreadable if you're closing long complex functions. We recommend using a lisp-aware editor, such as emacs. It will do indentation for you, will help you balance your parens, and will format your comments for you, if you like.