Here are a few:
When in the Immigration hall, join the queue nearest the one for American Citizens only. This clears quite quickly and they call people over from the next queue (this tip works best at Sanford).
If you are renting a car, send the drivers ahead to collect the car, whilst the rest of the party collect the baggage (ALL the drivers have to be present at the rental desk though).
DONT make ambitious late night plans for your first few nights. You will be up super early in those first days so take advantage of this and hit your "Must Do" rides and attractions at park opening. This will save you LOTS of time. Save all late night attractions till later in your holiday (Fantasmic, Illuminations, Spectromagic for example).
Eat your main meal at lunch time. Especially in the parks this can save a party of 4 upwards of $20 per meal. Also, look out for the coupon books to save 20% or so off many off site restaurants!
Take your own bottled water into the parks. It cost $5 for 24 sport top bottles at the supermarket...ONE bottle cost $2.50 in the parks! If you have a freezer, freeze a couple and leave a few in the car and a couple in your rucksack!
Ask to travel up front with the driver on the monorail...this is free, you MAY get a "pilots license" and its a great view! You may have to wait until one comes with the seats free though.
If entering Animal Kingdom at opening, go through the Rainforest Cafe (there is also an entrance / exit here). This bypasses all the crowds!
Use the FASTPASS system to its fullest. You will be surprised how many people have no idea what this is, so take advantage of it to plan your day.
Hope that helps a little!
Allie