While I agree with JC (above), there is some general advice to give:
1) Visit in any order you feel like that day, but MAKE SURE you look at the Extra Magic Hours (EMH) if you're staying on-property! The park that they tag changes per day, so if there is something I really want to do in that park, I tend to take whatever is on offer for that day! XD
If you're not on property... D: EMH makes my life easier, as does not having to park in the parks themselves. But that's just how my husband and I roll! In this case, seriously pick whatever you want each day.
2) As JC pointed out, this does give you a lot of flexibility. I, personally, always get one.
3) As for not missing things, people like different things! However, there is a new Legend of Captain Jack Sparrow ride coming out in Hollywood Studios, so you may want to do that. I predict LONG LINES, though. If you're a roller coaster fan, Rockin Roller Coaster (HS) and Expedition Everest (AK) are about as intense as Disney gets. Toy Story Mania (HS) is usually VERY popular, and the Fantasyland renovations in MK are done at last, so you should probably drop by to stare at it at least!
4) Crowds are wicked this time of the year. I'm going just after you, which will be worse if possible (XD) but don't get discouraged! Figure out which rides you can't live without and if they have Fast Passes. Then grab the FPs when you can and return later! Be prepared for long lines, and my advice is to find something fun to do while in them. My husband and I call it "the line ride" and you'll be on it a lot in the last week of Dec. We bring Whodunits, a Hidden Mickey book, and portable game systems to help out, and carry water and small snacks at all times.
Do NOT leave the park if it fills to capacity while you're inside (at least if you wanted to do more park things)! Not even to go to another park! You won't get past the gate and you won't get back in! This happened to us on New Years Eve one year, when our group got split up between two parks, lol. It turned out fine, but just keep in mind that at Disney, Full Means Full.
Best of luck!