I think the biggest three things are.

1.) Feed smaller meals

2.) Watch the snake

3.) Be ready with something to put in the rats mouth.

I think in general if you adhere to rule number 1 correctly then rule number 3 is a moot point. A small enough rat poses no harm (while it is dieing) to your snake unless it is capable of biteing an eye. The only way other then biteing an eye that a small enough feeder can do damage to your animal is if it left alone without supervision. The rat can begin using your snake as a chew toy.