Edit: Hell! It’s the best write up on writing practical LISP code I’ve run into. Thanks for posting. Wish we had a bookmark feature here …
The Lisp optimization notes are very good. One more I’d add is to avoid consing, which is somewhat slow in and of itself, but also causes garbage collection to run more frequently.
Peter Norvig’s book “Paradigms of Artificial Intelligence Programming : Case Studies in Common LISP” is packed with practical advice on using Lisp. It’s a bit dated, and I think Norvig himself even says it’s not a very good AI text any more, but it’s a worthwhile read for the CL programming coverage. The sample programs aren’t cutting edge AI, but they’re still kind of neat.
This is good stuff!. Chess-in-Lisp by Steven Edwards is another resource for writing chess utilities in CL. It’s a bit of a pain though to dig the latest version from forum posts.