Jean-Philippe Paradis over at HexstreamSoft has a nice page about getting started with the Common Lisp Hyperspec. If you’re already familiar with the Hyperspec, you’re probably with most of the material. If you’re not, it’s a nice introduction.
One thing that I found really helpful was detailed instructions for installing a local copy of the Hyperspec on your computer. If you often find yourself working off line, that can be a real lifesaver.
Paradis has a lot of Common Lisp material on his site so if you’re there for the Hyperspec introduction, take a look around at some of his other offerings.