1) We *do* believe in documentation. Document your dynamic variables, functions, macros and classes. Besides, provide a documentation from a wider perspective. Provide diagrams and arquitecture documentation; examples and tutorials, too. Consider using an automatic documentation generator (see the bitacora package in the dependencies). 

2) On the length of functions.
    We don't want functions to be shorter than the should nor longer than they should. There is no "every function should have at most ten lines of code" rule. We think that coding is like literature to a great extent. So you should strive for beauty and clarity. Again, that your code is object oriented doesn't imply that your methods will ideally have two lines of code and dispatch to somewhere else; that is not always good at all. It may be good from an object oriented point of view, but it is too low level. We want to think in terms of languages, that is higher level,  instead of objects sending messages.

3) Use destructuring-bind or let or a pattern-matching library instead of car, cdr, cadr, and the like to obtain more readable code.

4) Use widely known Common Lisp coding guidelines: http://web.archive.org/web/20050305123711/www.lisp.org/table/style.htm