Over the years I have tried different storage methods, however, have found the following to work the best.
Skiis: Make sure the edges have good wax on them, otherwise oxidation WILL occur. I hang them, loosely strapped at the shovel and tail so not to flatten the ski's camber. I sometimes loosen the bindings by 50% and mark on the skiis, with tape, the number of turns I made in backing the dins down. I usually us a degreasing spray agent on the bindings since they accumulate a lot of gunk over the winter, then spray a little penetrating oil into the working parts, and wipe off excess.
Boots: I make sure they have been dried properly so there won't be any surprises in green growing stuff over the summer. I make sure the buckles are fastened tightly to insure the shape of the boot will be maintained. I usually put the boots on in late summer and walk around for 20/30 minutes, once a month, to keep the bladders conforming to my foot.
Nothing is worse than putting boots on for the first day of the season and they don't seem to fit
due to foot changes or bladder bloat. Store them in a safe, dry, clean place. Most garages, attics, and the basement are not advisable.