We usually take this approach for MK: Get fast passes for our must-do rides for sometime in the late morning/early afternoon. Then we get to MK as close to rope-drop as possible. Then we head back to Adventure Land and Frontier Land and ride those rides first before the lines get long. We're usually able to get in Jungle Cruise, Pirates, Splash Mt (if it's open) and Big Thunder (usually 1-3 times) before the lines start getting too long. A note for MK if you haven't been there in a while: the Peter Pan ride gets really long really fast, so if that is one of the rides you really want to do, I would get a FP for it.
For AK we try to get a FP for the Safari Ride as early in the morning as possible. We've always had better luck with seeing more animals earlier in the day. Oh, and now there is FOP, so if you want to do that ride, you MUST get a FP, or risk waiting a very long line. It's an awesome ride!!!
For EP - If you MUST do the Frozen ride, get a FP for that as early in the day as possible. Head to Soarin` first thing in the morning. With the additional theater, the line doesn't get nuts quite as early in the morning as it used to. We then do Test Track in the single rider line.
For HS - if you want to do the Toy Story ride, get a FP for that for as early in the day as possible. We also like to get a FP for Star Tours, though we have found that the line for that one gets shorter the later in the evening it gets. So, if you are going to be in the park all day, you might want to wait until later in the evening to do this one. The last trip we were there we rode it 3 times back to back at around 8pm. We could've done more, but my body said "nope, that's enough for tonight, unless you want to be checking out the inside of one of those fancy garbage cans".
Have a great trip!