Former patent examiner here. This is the truth. Only thing I'd add is, read the claims broadly. Anything that could possibly be meant by the words in the claim.

If it's broad enough to contemplate what you're doing, look through the spec, correspondence (the "file wrapper"), and general knowledge at the time for arguments to restrict interpretation of scope. Also, talk to a lawyer :(

edit: linked to this in another comment, and it also belongs here: "Broadest Reasonable Interpretation" http://www.uspto.gov/web/offices/pac/mpep/s2111.html