1. Get a guide book or read through a good planning site for an overview.
2. Decide when you will go. I would check park hours and crowd levels to help decide this, along with any discounts that may be available for certain times of the year.
3. Decide how you will get there and how you will get around.
4. Decide how many parks you want to see. Only MK? All 4? Will you do the minor parks (water, Disney quest, etc.)? Will you do other non disney parks such as Universal, Sea World, Busch Gardens, or Legoland?
5. Decide how many days to go. I'd recommend at minimum 1 day per each park you decide to visit, plus 1 rest day, plus 1 repeat day to make up what you may have missed or want to do again. This will give you a general time frame.
6. Decide where you will stay. On property or off. If on property, which hotel?
7. Make a list of possible table service restaurants.
8. Make a Must Do atttraction list, an If We Have Time List, and a Don't Care List.
9. Make a list of other special activities at either the resorts, DTD, or the parks you may be interested in.
In general, you will want to make your travel and lodging reservations first once you have decide when and how many days you are going for. As early as possible to give you the best options, as some on-site rooms sell out as much as a year in advance.
Then you can start looking at all your must do activities, attractrions, and restuarants. You can start playing around with these factors and start planning, seing how you can put the puzzle pieces together to match up your park days with meals and rides you want to do in each park or at the resort you are staying at.
At this point, you should have a pretty good idea if you need to add more days to fit everything you "must do" in or not, so now is the time I'd start looking at purchasing park tickets unless you did a package when you booked your lodging.
I personally don't plan all of one thing and then all of another. It really is like a puzzle. You need to make sure it all fits in the time you have. I have my top choices of what attractions I want to do and where I want to eat and then a few backup choices in case my top choices don't work out. From this, I make a general plan or two. Then when ADRs (reservations) open up at 180 days, I make those based on my plans. If you are still undecided on times or places, make more than one ADR and drop the one you don't need after you see which of the two fit better in the FP+ schedule you get. Next, I make my FP+ reservations based on my original plan. This can be done at 60 days onsite, 30 off. Depending on availability and how far out I am able to book, I may need to revise my plan a little. This is where the multiple ADR may come in handy. Lastly, I work on the little details, like making sure I have directions for getting to and from places and any extra games or activities we will be doing.
