Assuming you have a receiver hitch mounted on your truck, get a ballmount that has as little drop as possible (straight is best):
A shackle with at least a 10,000lb load rating:
A good tow strap with loop ends:
Loop your tow strap around the anchor point on the stuck truck (so that both ends of the tow strap are at your truck), and then secure the strap to your truck with the shackle. At that point, your truck is ready to pull.
I always let the guy who is stuck hook up the tow straps to his own vehicle. You'll want to check where he has them hooked to make sure they're secure. If pulling out someone's stuck vehicle results in damage to their vehicle, better it's not your fault.
Tow hooks are much less secure than tow loops, as the tow strap/cable can easily slip off, so you want to make sure the towstrap isn't going to whiplash back and smack into your truck if it should break - put a heavy towel or jacket over the strap and this'll keep it from flying too far.
If you're using good quality tow straps, they're made to stretch. Rock your truck front to back and let the stretching work for you.
If you've got 4x4, shift into 4LO for the most pulling torque.
If you've got a locker in either axle, lock 'em up.
If you're in sand and you need a bit more traction, lower your tire pressures. Less than 5psi and you run the risk of popping the bead, so don't go too far down.
If you're in mud, keep tire pressures up.
It's usually easier to pull out a stuck vehicle in the reverse direction it was goint when it became stuck.