The only tips I preached when I taguht reloading was a)Close the door and don;t allow distractions, b) make sure you have the proper powder & bullet for the load you are doing, c) only one powder on the bench at atime, d) when returning unused powder to the can make sure it's the right can, e) for bottleneck cartridges
make sure they are properly resized, don;t set the shoulder back and make sure they will chamber smoothly.[/quote]
I would add to that like Caustic says get the headspace guages and have someone teach you how to use them properly. THEN only set the shoulder back a thousandth.
Any more than that will work harden the brass and cause case head separation. Otherwise Dun gives some great advice here. Especially the powder part. Also make absolutely sure that it is the right powder to begin with. I got to watch my buddy blow up a Wincherester 223 WSSM by using the wrong powder. He asked the clerk at the gunstore for XXXX powder and she gave him something else. He never even looked at the bottle and just assumed it was the correct powder. It cost him a good rifle and some pieces of his face and hands.
I would add. DO NOT handload when you are in a hurry or stressed out. You WILL make mistakes and they can prove fatal at worst and painful at best.