1: Winch cables store an enormous amount of energy and therefore a blanket or coat need to be placed on them to soak up the energy if they break. A long tow strap can also be wrapped around it 2 or 3 times as a substitute. Or better yet use synthetic winch line instead.
2: Tow straps also store a great deal of energy (see number 3) and therefore they also should have something to soak it up if it breaks.
3: Be sure the attaching points of each are secure and adequate. Do not trust the tie downs found on some stock vehicles. (They look suspiciously like hooks but don't be fooled) I had a friend that attached a tow strap to one of these. The tie down blew the back of his head up when it came through the window. Last I saw him he was out of the coma and was learning to walk and talk which were both extremely difficult for him. (Each sentence took two or three minutes and was hard to understand) He was lucky because his girlfriend that was with him was a nurse and kept him alive until lifeflight got there.
4: Be absolutely sure the footing and mounting points on a high lift jack are solid. They also store a great deal of energy and have been known to seriously injure people if they come flying out.
5: Keep people out of the line of winch cables, jack handles, and well clear of the area where your jacking.
6: If you jack your rig up then be sure it has some blocking before you get under it. Toss the tire under the axle if nothing else.
7: Block tires when jacking on hills. If steep then tie off to a tree with either chains or the winch. (Be sure to use a tree saver around the tree itself)
8: Inspect all equipment before each trip to be sure it is in good repair. This includes pulling the winch cable out and winding it back on the drum neatly. The cable will also last longer that way. If you get a snag in the cable clip it off right away so it doesn't get worse and to avoid having it tear into your hands.
9: Always use leather gloves when handling the winch cable.
10: Keep hands clear of the winch drum when the winch is in operation. Never ever trust someone else with the controller when your hands are on the cable. If there is any chance that you can get hurt by them accidentally hitting the button then make sure there hands are nowhere near the button. It's preferable for the person handling the cable to also handle the controller.
11: Wear long pants and a solid pair of boots. (Work or hiking, NOT cowboy boots) Both will help protect your legs and ankles from cables, chains and ropes if they brush up against them.
12: Avoid powering the winch out. (Freespool it out whenever possible) The way the winch is designed makes it such that this is literally powering it against the brake so excessive use this way will wear out the brake and winch motor. Without a good brake the winch will not hold the vehicle when it isn't under power.
13: Be sure the equipment is capable of the load that will be on it. For instance many chains are not rated very high even though they look adequate. Or 5/16" winch cable which is barely adequate for 8,000 lbs. can be pushed way beyond it's limits pulling a 5,000 lb. rig out of sticky mud.
14: Never use a winch cable for towing. The loads put on it if the line goes slack and is jerked on can break the cable and even possible the winch itself.
15: Axes were not mentioned but be sure you know how to use one if it is necessary. (Same goes for chainsaws, shovels, etc.) Don't laugh. Last year a fellow wheeler that was with us had to go to the emergency room to get stiches after he tried to cut his leg off. Fortunately it was only a 45 minute drive. Quite often though the places we go are much further from medical help.
16: Have a trustworthy spotter to watch things from the outside while winching. (They should already know to stay clear of the winch cable, etc.)
Perhaps I went a bit overboard here but all of these I think are important trail safety items.
