This achievement takes time but keep at it.
If you come across a certain jump where you can't seem to get enough points before the landing, just go to the editer and put a bigger ramp there.
On troubleing Snow Quests, the same thing applies. Simply add ramps and rails to add to the line.
On Samurai Slaloms, remember that holding both triggers down = top speed, and to use the appropriate trigger for those sharp turns.
Also you need to get the number of people to repect you with awesomness one each mountain section, this counts as a gold medal
(If I left something out I apolgize. If anyone needs further advise just message me and I'll happily answer the best I can ^^ )