The following is by no means a comprehensive guide to the rules and regulations on driving in Florida. But is more of a personal recollection of my experiences during the many times I have driven in Sunshine State.

For some of you this maybe your first go at driving in the USA. Maybe you're concerned at how you will manage driving on the right hand side of the road.
What about junctions! Traffic lights! Toll roads! Overtaking on both sides!

How will I manage?

Firstly do a bit of research, your reading this so you've already started.

On the Flight

I have found that most of the airlines that I have flown with give a short video presentation on driving in Florida during the flight, take the time out and give it your full attention. I found this most useful especially on my first trip. It is also good as it gives you up to date information.

At the Rental Car Park

My first recommendation is familiarisation of your rental vehicle.
Walk around your rental vehicle and get to grips with its size.
Read the vehicle user manual to find out about the air con / demisting, the indicators, the window wipers and lights. Better to take the time and get to know how it all works before you set off on your journey. You will have enough to concentrate on without trying to find out how to turn on the wipers when it starts to rain.

Look at your map and plan your route before you start your journey. Most holiday home owners will give you a detailed route plan from the airport to their rental property. If not then I found the rental company personnel were very helpful if you asked for a route plan to your rental area.

On the road

When you start your journey please pay attention to all traffic signs and note that the speed limits are lower in Florida than in the UK. When driving on the interstate traffic will pass you on both sides so pay attention to your mirrors and always check before moving lanes.
Road signs for turn offs are displayed well in advance so you shouldn't be caught short and miss your turn off.
Toll roads are normally a bit quieter than the Interstate so if you're travelling from Sanford Airport to Orlando, I would recommend the SR 417 toll road.
Toll booths are clearly signed and sectioned into lanes for pass holders, exact change and change given. Most of the main toll booths are manned but exact change is required for some of the booths that exit the SR 417 as you near Orlando.

Driving in Orlando is very straight forward. Junctions are clearly marked with guide lines painted on the road, making left and right turns easy.
Traffic signals are suspended above you. Be aware that signal changes are very quick so be ready to stop if required.
Road signs are also suspended above you as you drive along the road. The signs are not the road you are on but the road that you are crossing.

The best advice I can give is to take your time and think before you proceed.
If you rush you will make a mistake. Nipping out into that small gap will lose your concentration and making that wrong turning will have happened before you know it.

Best Advice

Enjoy your driving.
Travel throughout the state and see all that Florida has to offer, not just the theme parks.
But most of all stay safe and have an enjoyable and memorable holiday.