Dan Shapiro has written a good post on this: http://www.danshapiro.com/blog/2010/09/how-to-read-a-patent-...

To summarize, he says:

1. Skip the title

2. Skip the drawings

3. Skip the abstract

4. Skip the specification

5. Find the independent claims, and read them

6. Back to skipping – toss the dependent claims (any claim that starts with “The _____ of claim _____” is essentially a refinement or detail of the parent claim).