I made one 2 years ago, it was a pain in the ass but i got it.
-Make sure you tell him that skiing is an extremely physical sport that is great for the body.
-You will probably have to take a short 30 min lesson (It's worth it for a day of skiing) just to say that you are learning while on the trip.
-You better start booking passes and bussing to the hill's, the sooner = Cheaper/Your choice of hill you would be suprised how fast they sell out of group lessons.
-Type up a rough copy of the form to show him, Include stuff like must where helmet.
If he approves then:
-Get awareness, my first year all i did was put up some poster's around school and nobody really knew about skiing/snowboarding in my area.
-Keep everything to the bare essentials, no point organizing a rail jam/ trampoline stuff as not that many people are into it as you are. And sorry, most people coming to your club will be gapers.
-Night trips are often better as it won't affect any curricular involvement.
-Plan a end trip. This year my club is going to TREMBLANT for a 2 day stay. Everyone from the school wants to go but I made it so you have to go to 4 of the 8 trips in order to go. The more people you get the less the bus cost's remember.
Make a video for next year. It is really good for showing your school how much fun skiing can be (stay away from dub-step for this video)