Lessons. My friends runs a ski school, and offered to give my 3 year old lessons. I learned a ton watching her, I was doing so many things wrong. Excercises with one ski on, picking up toys. creating toy obstacle courses, making everything fun, not putting on their gear (allowing them to do it, regardless of ohow ineffecient). The best thing about lessons if avioding drama (you made me fall!).
We just started our three year old on skis this winter, and I'd like to think we learned a few things. Many schools around us don't start instruction until at least four with most beginning instruction at 5 years so we took the attitude of building the Stoke so to speak.
We started with having her come out to the ski area by us and watched dad ski from the comfort of the chalet. This could be watching anyone ski really but it was fun for her to cheer dad on.
After that we planned an outing wherein our goal was low (2 runs). Having a season pass made this worthwhile because toddlers ski free a lot of places.
Every time after that, we upped the run count a little more but stopped short if her interest flagged or she started looking tired.
Snacks and frequent breaks are the name of the game too. As far as equipment, an edgie wedge or tip-tie along with leashes are a must.
I found it best to keep the instruction light and simple by limiting it to the following concepts:
Look where you want to go
Bend your knees
Pizza / French Fry
Hope this helps a bit! Our daughter loves it and that makes me feel great. At a later date we'll try lessons but for now it's all about fun.