first shot: shoot in better lighting, don't shoot at his ass, get a better background
second: really simple but probably the best in the set other than the last sequence, get lower and closer for a more dramatic shot, background is still a bit distracting. (see how much better a shot looks when the snow has good detail like that? compare it to 1, 3, and 6)
third: similar to first but has better lighting and a little bit better of an angle, background still sucks, snow is blown out
fourth: not going to comment on this one
fifth: can't see the skier, you need a flash especially since he's wearing black, shoot from downhill so you see his front instead of his side/back
sixth: trees are annoying, sky is very bland, looks soft, not a bad attempt though
last: much better than the first sequence, colours are good, sharp, skier really pops out, unfortunately you cut some of him off and are still shooting from uphill, but i like this one.
there's a lot more to be said but i hope i covered some basics for you