The best thing to remember is...
to go slowly! After the snake eats and it is down as far as it will go in his belly, it should look like he ate a decent, but not huge, meal. You should be able to easily notice that he ate, but the scales should not be hugely distended.
If you feed too much, it will probably cause a regurge, and then you have to go to the regurge FAQ, and follow carefully - a real pain! So only increase the food size gradually, and hopefully you (and your snake) won't have to go through that.
Also, put cuts into any prekilled mice. That helps it digest more quickly and completely, making it easier for the snake to digest a bigger meal.