Entropy

The title of this article is actually “10 Tips for Optimizing MySQL Queries that don’t suck” - and its worth a read. If you are in any way involved with web 2.0 you almost definitely will have a database bottleneck at some stage, and these will help you improve it or even better - do it right the first time!

10 Tips for Optimizing MySQL Queries

The article is essentially attacking this post on optimization tips - which should also actually be read.