Winching can be dangerous. There are certain things that should be done and followed, not only for your own safety, but for the safety of others and the environment.
Check your cable before you go out. If it has any frays or kinks - replace it! Don't take any chances. A winch cable snapping under a load can kill someone. I have seen some very nasty looking cables with a bunch of kinks and frays being used over the years. Luckily I haven't seen anyone hurt or killed. Very lucky I should add! I have seen the damage a broken winch cable can do when it breaks.
There are a couple of things you should have with you for winching. Have some heavy gloves for handling the winch cable. You hands will thank you for it. You will also need a few some "D" shackle of size, short length of 3/8 chain and a good pulley block rated at twice the capacity of the winch. You will need a "D" shackle for connecting the tree strap you will also need. The block is for doubling your pulling power and a few other things as you use your winch more and more in tougher and tougher spots.
You can get all these things in one neat little package form the people who made your winch usually. They call the package an accessory kit.
I think the tree strap in most of those kits are too short and not wide enough. This must be the environmentalist in me. One thing I hate seeing is a tree scared up from people wrapping their bare cables around a tree. Doing this will kill the tree in time. Use a tree strap at all times. I like using a tow strap six inches wide and twenty feet long. Not to be confused with a snatch strap which stretches.
When you do winch throw a heavy coat or towel over the cable while you winch. If the cable breaks it helps the cable to fling down instead of up into the air where people's heads are.
When you first buy a winch or after using it on the trail you should rewind it. This help protect the cable from damaging itself when used next. To do this be on flat ground and hook to something like a telephone pole if you are at home. Let the cable out almost all the way. Then winch your rig to the pole. Make sure it doesn't over lap itself and that there are no gaps between the cable.
Have fun and be safe.