I'm so sick of how people say "should I do this to my skis" or "I can do a 720 in the park which makes me such a good skier."
Good skiers can do all of the mountain, including the steep stuff. If you can only ski park, you're NOT A GOOD SKIER. Park rats, get that through your head. Good skiers also know how to use the tuning of their skis to their advantage or how to use the width of their skis. They should also know what they are buying, because you don't buy a ski "just because they are sweet T-halls and theyre supposed to be the shit." Demo your skis before you buy, and know how to take good care of them.
Don't talk shit about what you don't know either.
This is all I can really think of now.