As you are still looking at this topic I will add some more comments and suggestions.
You dont say how old you are, who will be going with you, and the ages of any people in your party, but some general things to think about:
You have a choice of booking an "all in" holiday with a company like Virgin where you get the flights, hotel, possible a hire car etc.
Or you can stay at one of the Disney hotels on the Disney complex. This has advantages as Disney provide buses to all the Disney parks, but it is not cheap to stay in the Disney hotels.
Or you can "do it yourself" and book the flights and accomodation yourself.
If you "do it yourself" decide if you want to stay in a hotel or in a house. Many many people rent out houses in Orlando so you can rent a house off them. Of course there are advantages and disadvanatages in staying in a house. For example houses are more isolated and not near shops and restaurants.
Decide if you want to hire a car or not. If you stay in a hotel they often provide buses to take you to the parks, but it is much much easier to have your own car. But that does cost extra but gives you lots more flexibility.
Think carefully about theme park tickets. Ticket prices for individual days are VERY expensive and both Disney and Universal offer tickets for longer periods (like a week or two weeks) that cost far less per day.
However these can still cost hundreds of dollars each so you may want to buy Disney tickets for one week and Universal tickets for the other week.
As I said these parks are huge, and you can do a lot of walking, so think carefully if you party includes children or older people.
You can also get "theme park burnout" if you go to a theme park every day so it is good to vary it, maybe a theme park one day, and a water park the next day and so on.
The queues can be very long for rides so try to get to the park early before the crowds get there, or stay there late after the crowds have gone. If you get there early go round the park ANTI clockwise as most people go round clockwise.
Take a rucksack and make sure you have plenty of liquid as it can get very hot.
Be prepared to spend a LOT of money. By the time you add up the cost of flights, hotel, hire car, theme park tickets, food and drink it can easily cost £2000 or more per person.
If you need any more help just ask.
Here is a good web site and book that may help you the "Brit guide to Orlando"
http://www.britguideorlando.net/