I think there are 3 strategies mentioned here that could all work for folks in general. (adjunct strategy is to keep trying for a fp+, particularly as people cancel things when your date gets close. One caution... if you "delete" a single fp+ reservation when you have your 3 set up, it creates a huge mess... as someone mentioned, look to the mesa guy fp+ post about changing fp+ reservations to make sure you don't give your self any headaches.)
1) Rope drop+ -- Get there EARLY. Note that some mornings we have experienced issues with the boat or the monorail, and even though we got there early we did not make rope drop due to delays in getting past the damn lake.
2) Be our guest reservation. -- This is highly likely to work.... there HAVE been mentions of glitches by cast members that messed up this strategy... but I would do this one if it is available, and you don't mind getting there really early. Added benefit to this strategy is that if you like Peter Pan you can likely get on that right after 7DMT with a short line, and so you have gotten two of the attractions with the worst lines out of the way early. Huge benefit.
3) Ride during/after wishes -- This one is my favorite, and can be used in conjunction with the first two of course.. While I like 7DMT, it is a short ride, and frankly I was expecting a bit more. If you get the chance ride it DURING wishes, I find it to be a game changer. One of the best experiences we have had in the Magic Kingdom was riding while the fireworks were exploding overhead. It is a little tricky to time it, so you have to be a little lucky, but if you can make it happen it is really neat.
Ed