I learned a couple of lessons during my first GS:
1) Priority Club posts their activity date as the check out day while HH and BW use check in date. I could have stayed at an IHC property the week GS2011 started an got an early hit.
My sixth hotel hit was going to be this Monday, November 14th at a HIX in Portland, but that wouldn't have counted. Luckily I did a one nighter at a BW and got the 6 hotel hits.
2) Read, and re-read the rules. I hit one foul ball by converting PC points to DM on points.com rather than going through PC. Expensive "miss" on my part as most of my PC reward nights are only 15,000 points.