I have three different "plans" for three different situations.
#1. I'm at WDW with the kids.
We try to figure out which park they want to go to. Then they say what they want to ride first. (I try to stear them toward a big ride that would have a long wait later on.) We then finish up that land and then move on to the next one. At some point we get fast passes for something that will be a little later that we know that we will need them for. Normally we start on one side of the park and finish on the far side, back tracking only to get fast passes our while waiting to use them.
#2. I'm at a park by myself that I've been to at least twice before.
I start with my favorite or one that I know gets a long line later on. I do all the coasters / big thrill rides / water rides in that area and then move on. I try to mix up the coasters some. I don't want to do all the multi loopers or woodens all back to back. As an example, if I'm at BGA I would start with Kumba, then do the water rides back in the back, then move on to SheiKra, then Qwazi, then Montu, and then finish the first round with Rhino Rally, Scorpion, and Cheetah Chase. At this point, I usually take a break; I would eat lunch, walk around looking at animals, ride the train ... Then I finish up with a big coaster run: Montu, Scorpion, Kumba, SheiKra, Gwazi, Sheikra, Montu.
#3. I'm on an out of state coaster trip to a park that I've never been to.
I start with what I think will be one of my favorites and I expect will have a full queue later. This is normally a hyper / mega, a launch, or a multi looper. If the place has a new ride I usually go for that first to avoid lines at mid day. I normally work from land to land but I do skip around some (as before no two woodens in a row, no two multi loopers in a row, no two lauches in a row ...). I try to finish big with one of my favorites or one of the big coasters that has a shorter line at the end of the day. If I'm there at dark, I try to find a ride that might be even better with limited lighting.