Now that we are less than a week away from the end of GS 11, it may be a good idea to pause for a moment and sum up any lessons we have learned from the past two months. It can be helpful as a jumping off point for GS 12. I am a firm believer in not "reinventing the wheel."
Let me start by a bit of personal experience. This was my first GS, and I expect to get 36 hits and 1 insurance hit.
1. START EARLY / FINISH EARLY. Ask yourself what 100 (or 110) thousand miles are worth to you, and then budget your purchases with this holistic view in mind. Get your hits at the very beginning, and then relax. This is better than obssessing about whether or not each hit is "worth it". This will save you incredible amounts of time, and time is valuable. I thought a long time about whether I should do the Teleflora, for example. Finally, I just did it - after plenty of wasted time.
2. DON'T SPEND HOURS TRYING TO SAVE TWO DOLLARS
Yes, it's great to have a low CPM, but sometimes, we go a little crazy. Think of time expended in relation to the dollar or two you might save.
3. DON'T EXPECT MAJOR DEALS AND CHANGES TOWARD THE END
I often hesitated thinking that US Air would pull some rabbit out of its hat as November approached. This did not happen. Yes, there was a change in policy about Audience Rewards, allowing Trivia answers to count as hits, but considering some of the cheap tickets, that only ended up saving about 11 dollars. Similarly, not funding brokerage accounts is not really a savings at all, as they pay the same interest as your bank account. There were a few hotel transfer discounts toward the end (SPG) but they were balanced by the hotel transfer discounts expired early on. Similarly, the 100% bonus on purchasing miles the first two days of the GS proved to be a deal than many lost out on by not using, as miles are now much more expensive to purchase (I bought 10K and got 20K, and am glad I did).
4. MOST PROBLEMS ARE RESOLVED OVER TIME
Another advantage of an early start and early finish is that it gives time for problems to be resolved, either on their own or with a phone call to a hit sponsor. If you do find some sort of break early on, which is later eliminated, at least you will be "grandfathered in." Late starters/finishers can only say "I wish I had done that. This strategy tends to eliminate worry and save a lot of time. You see clearly in the first or second sweep what the problems are.
5. ASK QUESTIONS EARLY
If you have a special question (e.g. Hotel or car rental no-shows), ask it early, and as you are probably not the only one with that concern, you will probably receive a quick answer...then ACT.
6. PLAN A TRIP FOR SOMETIME IN THE PERIOD
Nothing gives you a chance to rack up hits as a trip (even a short, close one).
and finally...
7. THINK LATERALLY
I have four kids, and all have authorized user cards (which I keep). Yes, you can get authorized user AMEX cards for kids. Had I planned this from the beginning, I would have replicated my purchases so that I would have ended up with about 140,000 miles per child. That's what I intend to do next year. Set up separate email accounts for the kids, to prevent their own email accounts from being innundated, and use the same password for all purchases, memberships, etc. That keeps things nice and simple.
This "multiplier effect" can be used efficiently and to the greatest advantage.

Well that's my two cents. Please feel free to add your opinons and tips.