My two cents:
I started some light studying at the beginning of this year (January 2013) and really kicked it into overdrive for the last two months before my test date on September 24th. Here's what I learned and what I wish I had done earlier.
1) In my experience, I found Peterson's guide (maroon and gold) to be almost useless, aside from the math review section.
2) Similarly, I found the
Manhattan GMAT Verbal books (IR, SC, CR, Essay) absolutely invaluable. Although I suspect their strategies might be a little too rigid and inflexible, their thought process is truly remarkable. I found that underlining specific sections & paragraphs, then rereading those same highlighted sections every night to be very helpful to me.
3) The official GMAT problems are great practice, even more so when you force yourself to fight the clock.
4) What I wish I had done differently: learn the material, but remember that you're learning the material to be able to apply it to the test under timed conditions. I think I spent too much time focusing on mastering the material rather than practicing taking the test. I truly believe that if you first study any rusty material, then practice timed problems every day for several weeks in a row, you'll be just fine.
Best of luck!