There are three BIG tips.
1. Don't be in a hurry.
2. Don't be in a hurry.
3. DON'T BE IN A HURRY!!!!
Chains moving too soon can cause huge problems. The box should wait to flip the down until signalled to do so.
When I get a box man who's in a hurry and flips it too soon I'll get confused at least a couple times a game. I have rubber bands on my hands to keep track of the down, but I generally look at the box and add one. If it's flipped too soon, I'm adding one to the wrong number.
Chains, wait until you're motioned to move. There's time to set up. Even with the new rules where the clock can start and the play can be run in a no-huddle, the box should be in the right place for 1st down and the chains can be set up on the box.
Now, as I've mentioned, don't be in a rush, but hustle when necessary. I can think of a couple of chain crews that would ease on down the sidelines, even when their team was trying to move quickly. That's no good either.
Oh, and finally, drop the stakes and get out of there if the play is coming at you.