Wotcha mate...
As dwifty said....air down your tyres a bit to give a bigger footprint...
a/t's are better than m/t tyres,
but gentle use with m/t's is ok, just dont let em spin or they will dig quicker than a mole on speed!
If you do get a bit stuck...STOP...
and dig the sand out from in front of the tyres and drive and gently....
Dont keep trying as you will never find the bottom on a beach, and you will then get really stuck...
One trick that can help when you have dug the sand out in front or behind the tyres, is to start the car in lowfirst or reverse and crank it out on the starter motor...this is much slower than driving and will stop it from digging the holes bigger...
Reversing out of a hole is often easier than trying to carry on forwards, as gradient of hole is normally shallower..
Always extract down hill...let gravity help you (assuming you are above the highwater mark!)
Try where possible to stay above the high water mark...then if you do get stuck, you havent got the incoming tide to worry about as well...( I have been there! It does increase your sence of urgency to an unpleasant level!!).
I have seen about 10 motors get taken by the sea in the last five years that I have lived at the beach....the newest one a 2 year old disco!
Staying above the high water mark is also good for your car, as the salty wet stuff will corrode all the awkward to get to bits of your car in hours!
Make sure you pressure wash the underside of the car thoroughly after playing on the beach...
Dont drive in the sea...it will kill your car, and the sand is far less stable to drive on when it has water over it...remember standing on the beach as a kid and as each wave comes in your feet sink more???
Avoid driving over water run-outs on the sand...again can be real soft there and swallow a car, if you have to cross one, walk it first, then take a run at it!
Momentum is your friend, move a steady pace in a highish gear in 4x4 (dont just use 4x4 after you have got stuck!), avoid sharp turns and pick your route so you can keep moving without stopping...Avoid having the engine revving high, as will enduce wheel spin...and digging!
If driving dunes, check what is the other side before going over the top, it could be really steep on the other side and you will bury the nose in, or high centre your truck...the loads of digging will ruin your day!
Sand dune jumping is fun....but get it wrong and you will land on the nose and rip the front suspension out (been there too) or if you really unlucky you will roll it lengthwise which make quite a mess...(if you are gonna do it, mash the throttle as the front wheels get airborne which will pick the front up a bit more, so that the rear lands first...and be ready for the front to bounce airbourne again as fronties dont really have enough front travel for this sort of stuff)
Finally...as tempting as it is to bang it in 2wd, floor it and do donuts in the sand....
you may easily find that it is your door mirror that is stuck in the sand not your tyres!!
So easy to happen...soft bit of sand, or a slight rut, and a tyre will dig in and over she goes...
not done this one myself but had the yella fronterror up on 2 wheels when a powerslide on the beach got a bit more crossed up than planned!!
Needed a Fag after that one!!
Extra kit to take....
shovel,
a couple of bits of old carpet (lay em in the boot and the dont take up any space),
long tow rope and shackles,
sunblock

,
air compressor or foot pump

for tyres (to pump em back up),
something strong, flat and about the size of a paving slab (to stop your jack sinking),
hi-lift if you've got one and your car has suitable jacking points (worse case scenario you can always jack up the wheel with highlift in rim...steels are good for this, alloys will mark but it its gets your car out you can touch em up later)..,
A couple of wooden blocks to give standard jack a bit more lift if no hi-lift (sods law says there will nothing on the beach to use!),
a couple of rachet straps (useful to secure a spinning wheel by straping the wheel itself back to a tow point...will then transfer drive to the wheels with grip if you are crossaxled),
Gardening gloves as sand dune grass will cut your hands to shreds,
refreshments as digging can be thirsty work. (not beer though...or you will still be stuck the following day and digging with a hangover!!)
Have fun matey....

and I hope this helps...
laters
Gregster
Ps...I might go to the beach in a minute to take the dog for a walk...dont need the car though as only 150yds away!! Love it!!

Tractors are good on the beach...we used a john deere a couple of years back with a 4 furrow plough on it a while back as a lazy way of digging lugworms...
1/2 a bucket of em in less than 10mins!! amazing what 60grands worth of kit can do!! (thank god we didnt get it stuck though...)