the best info i've seen here is to go with a buddy... most of all to have a way home if you get stuck, or even worse, break something. you gain experience fast from getting stuck, and even faster from breaking things. both are something that WILL happen if you are a loyal jeeper, so prepare for it.
recovery points are crutial. I've seen too many cases where a vehicle could have been easily pulled out of an obstacle, but was in for longer than expected because of no recovery point. and don't think that just any point is good... it is best to have multiple points, many times it is important to pull on a certain half of a vehicle so it doesn't end up in a worse mess.
a shovel is a good idea, as well as a strong leverage bar. when you are caught up on the earth, and you can't move the vehicle, you might have to end up moving the earth.
a length of STRONG chain is also a good idea to have. often times, a vehicle may be in danger of a near rollover, or is on a hill where falling, or even worse, trapping or crushing someone is an issue... if you can chain the vehicle to a sturdy object such as a tree, or a well secured vehicle.
a mechanical recovery device is ALWAYS a savior. whether it is man powered or motorized, winches and come-alongs will work wonders where traditional recovery is not an option. sometimes you have to get creative with that stuff... one time, I was called to recover a cherokee who had been driving some long-ignored trails in some really deep snow.... we had a come-along, no trees around to hook to, so i ended up going back to get my plow... driving at 15 mph, dropped it... there was our anchor... we ratcheted him out in about 30 minutes using my jeep as an anchor.
communication devices are also the difference between a night in bed, and a night out nowhere... they all have flaws though... a CB radio is good to have, you can talk to anyone out on a public channel, and someone is bound to hear it... that is IF someone can recieve your signal. sometimes you will find that you are in a place where your signal goes as far as the hills around you, and that is it. a cell phone goes the same way, it is only as good as the signal... but if you DO have a signal, you can always direct your call to who you want, and to someone you know can get you help... of in worst cases, you can call the emergencyy rescue services.
anything the vehicle uses is a good idea to have in order to replenish... water/coolant, fuel, oil, washer fluid, transmission fluids, brake fluid, steering fluid... etc... as well as any repair items... tire patches (i've used MANY MANY plugs in my days, even put 3 plugs together to patch up a sidewall hole in a tire caused by a sharp rock, still holds perfect pressure as a spare to this day)... wrenches, hammer, portable torch, hatchet for stumps and roots, and other basic hand tools... then there are the specialty fluids, PB Blaster is amazing to have, i once got my air filter soaked to where i was pulling moisture into the intake, and was sputtering terrible... i sprayed the entire filter with blaster, and within seconds, it was running perfect again. it is also good with stubborn bolts during repairs, and makes a good protecter against rust due to its very slow evaporation. WD-40 is a good evaporating water displacer for drying out ignitions and cylinders. there are fluids designed to dry water out.. but i've always had good results with these two fluids. spare spark plugs, Ujoints, shafts, battery, wires, assorted bolts/nuts, assorted hoses and hardlines, wire ties, tape, string, and other widely used items are good to have around for simple, but crutial repairs.
and if you plan on doing repairs, you may have to get under the vehicle. a jack will allow you to do just that... and not only do you have to raise it up, you have to keep it up... blocks or stands are often crutial in emergency repairs. often times, a log or a rock may be accessible to use as a stand, but make sure it is suitable for holding the weight. not only is raising a vehicle used for repairs, but is also a very good technique in recovery as well... often times, before pulling a vehicle laterally from an obstacle, lifting it out will free up some options as to where you can go with it.
i will finish off with some items of personal comfort/safety... first aid, blankets, tarps, flashlights/batteries, flares, firestarters, food/water rations, rags, toilet paper/napkins, extra clothing... etc... they are all things we hope we don't ever HAVE TO use... but should have access to in worst case situations.
Now I realize that nobody has ever seen a jeep pulling a U-Haul behind it, which would almost be enough to carry all of this equipment. And this is only a portion of the equipment that can be considered for the trails... Before any outting, consider the possible dangers, think of what you may need, before you may need it. If you do go with a buddy, or buddies, split up the cargo, or ask what they do have so you can drop yours for something else you may need.... Remember that there is no such thing as a "pansy" on a trail, safety and preparation are way too important to let go of... look ahead, check what's in the trail on the other side of the hill.. check how deep that mud hole is... check how deep that water is... can you fit between those trees?... will that rock hold its ground while i'm on it?... will this trail give out and drop from below me?... don't be afraid to get out and use your feet, they are not just for the petals... they are a good way to make sure that your tires will be able to stay where they belong, and stay out of where they don't belong... be safe...