What should you do?
What should you NOT do?
I assume you meant the above?
Do setup the camera ahead of time and use it.
Do walk around with it, aim it, get the velcro or whatever mount outlined on your helmet so you can repeat the attachment location easily.
Do check footage frequently
Do neatly pack the wiring and harness, leaving extra wire so you can take your helmet off with out choking yourself (that is the big advantage to the all in one devices that don't need wires... cause you will leave something unplugged, I guarantee it!)
Do check footage frequently (yes I am repeating myself, but it is important)
Do recharge batteries all the time. Note that rechargables normally operate at a lower voltage and therefore you might need more to get to 12 volts or so.
Do turn it on and off to ease the amount of editing that later has to be done.
Do use it to film other people.
Do get your act together for using it / setting it up. Sledders hate waiting for people when there is fresh snow out there.
Do sacrifice your ride to get the shots. You might not have as much fun, but you have to be somewhat more focused on the video then on the actual riding.
Do try and plan things out for footage with other riders.
Do figure on using about an 1/8 of the footage you take. The rest will look good, but not worth spending the time to put into a movie...
Don't assume you got the whole days worth of footage without ever checking it. Nothing worse then thinking you got all these excellent shots, only to find that you have 2 hours of snowmobile noises and a black picture.
That fricken sucks when that happens
Don't use it to only film yourself. Size definition sucks especially in low light, and you think something looks really cool and you got it, but really you end up looking like a spode, and deleting in anyways. Or you keep it for yourself and keep telling yourself how much larger it was and how cool and good of a rider you are.
Don't assume it is working, because it isn't and you will get the black screen like above...
Don't assume your fellow riders care anything about what you are trying to do, even though most of the footage will be of them, and they are the ones YOU will be watching....
Don't be upset when you make a plan for filming and no one listens to you and then they all leave to go to the next play area while you are screwing with your setup cause you took your helmet off and left something unconnected.
I hope this helps.. I have been thinking about the VholdR one, that does the compression to the card. Nice simple, no wires. Have I mentioned I hate wires?
I had a setup mounted to a canon video camera... I didn't use it at all last year if that tells you anything about my type of setup. Plus I also lost the ability to use the canon as I didn't want to take the cables apart...