If you're on Facebook, there's a group called "it's Orlando time" which is very useful.
Otherwise...
1- do you want to stay on site or off? Off site is cheaper, but you'll (realistically) need a hire car to get around. Staying onsite is more magical for the kids, and includes free and frequent transport to all Disney parks. Different hotels have different benefits, eg Caribbean beach has a gondola that connects to Epcot and Hollywood studios- very convenient.
2- what parks do you want to do? Disney is great. I'm guessing your kids are under 5, so universal probably isn't for them- most rides are bigger and the themes are aimed more at an older crowd- Harry Potter etc. There are some strong opinions about seaworld but their shows are fantastic.
3- are you going to pay for genie+ and lightning lane to skip queues (at the risk of being attached to your phone all day) or are you just going to go with the flow? If your kids are younger then the smaller rides do often have shorter queues so may not be worth the cost.
4- are you eating in the parks or not? Eating in Disney is arguably more convenient but the food is more expensive than out of the parks and not a great deal of variety. Lots of burgers, chicken strips etc. You can take packed lunches in but then you have to carry them around all day (and prepare them in the first place- much easier if you're staying in a villa vs a hotel).
5- how well will your kids cope with the walking/heat? The parks are huge. Fairly common to see kids up to 5/6 in push chairs- added bonus of somewhere to put bags etc.
6- are you going to go to the parks early, go back to hotel for lunch/nap and then go back to a park on the evening? Makes the day easier for kids but only really doable if you're staying in a Disney hotel with the free buses.
7- which parks are you most interested in? Look at maps/rides/shows in advance to plan what your "must dos" are.
8- currently you have to book days in the parks in advance (brought in to restrict numbers when covid started). This MAY be lifted but probably safer to book days and then not need them rather than the other way around. Once you've visited the park you've booked, you can go to another park after 2pm (but only if you've been to the one you booked!)
9- are there any experiences you particularly want- dinner at Cinderella's castle, makeover at bibbity bobbity boutique? These need to be booked well in advance
10- any sit down Disney restaurants you want to eat at need to be booked in advance- can book up to 180 days in advance. If you're staying onsite you can book for your entire stay 180 days before check-in, if you're staying off site you can only book a day at a time (obviously can book all in one go if it's less than 180 days)
11- most hotels (including Disney) charge per night for parking a hire car there- this isn't usually included in your initial booking and is paid on either check in or check out
12- get your ESTAs sorted before you book anything- having the same name as someone on the no-fly list can cause major problems. If you need a visa it can take many many months and your flights/hotel are very unlikely to be refunded if you don't get it in time
13- most Disney tickets include "memory maker", which is the official photos taken on rides and around the park. Make sure to collect them at each ride (usually by scanning your ticket) and download them from the app when you get home- they're only available for around 45 days
Can you tell what my favourite holiday is!!