IMHO, here are the most important things:
Most importantly...don't handle them if your hands smell like food. Wash your hands thoroughly after you handle mice or rats or whatever before you handle a snake. Then:
1. No quick, sudden or jerky movements. Be smooth.
2. Don't hesitate. once you've committed, do it. Be confident.
3. Don't restrain him. Don't clamp down on him and try to keep him from moving and don't hold him behind the head. He's not a venomous snake, so if he does tag you a little, it's no big deal. Just let him crawl through your hands until he settles down. If he starts crawling out of one hand, put the other in front of him , when he crawls out of that one, put the other in front of him. Let him keep crawling until he settles down. Make sure you are completely supporting him so he doesn't feel like you are going to drop him.
4. As has already been said, if he does bite you, just let him turn loose. No biggie. Just don't jerk your hand out of his mouth or you can injure him. Rarely, if they think your hand is food (like if you've been handling mice and didn't wash your hands), they might actually start trying to constrict and swallow a finger. That can get a little uncomfortable with a big snake, but it's still not a real big deal. He can't eat you, and even if he could, a finger is a terrible place to start. Don't use alcohol or ammonia or anything else like that and don't hold him under water. Reserve those tactics for dangerous animals such as big pythons, Gila Monsters, etc. (Although with the big pythons, bending the tail back sharply will usually make them release you) Gentle upward pressure on his snout with your other hand will usually convince him to turn loose. Just don't panic, let him figure out his mistake...it won't take too long. Then you figure out YOUR mistake and don't repeat it.
5. It helps if you can feed him in a container other than his cage. That will reduce the possibility that he will think that every time you open his cage, the next thing to come in is food. Feeding response bites are probably the most common bites in captive snakes.
6. If you open his cage and lift his hide, or open his hide to get to him, let him have a second or two to figure out what's going on. When he's in his hide, that's his sanctuary. when you go in there, you are invading his safe place and he might bite defensively. If you give him a second or two and let him crawl out into the cage on his own, he'll realize he's not being threatened.
I disagree with the practice of using leather gloves to handle harmless snakes (or any snake for that matter...they are virtually useless against most venomous species anyway). There is a much greater possiblilty that the snake's teeth will be pulled out in the event of a bite with leather gloves on. I'm not passing judgement on people that use them..lots do. But, if I was that afraid of being bitten by a non-venomous snake, I think I'd find another hobby..like collecting butterflies or stamps or something that doesn't have teeth. I think that using proper handling technique can reduce the likelihood of being bitten to the point that measures such as gloves are unnecessary. I've seen people use hooks and welder's gloves to get a 2 foot long Cal King out of his cage. Why don't they just go the rest of the distance and use light-reversal transfer boxes and Pilstrom Tongs?