Wear sunscreen. You will burn much easier at high elevations.
Bring layers. Weather can change very quickly in the high rockies. Although it can be hot during the day, temperatures drop off quickly once the sun goes down. Having extra layers will help you stay warm and dry.
elevation sickness PREVENTION
Drink lots of water to stay hydrated.
Take it easy—especially for the first few days.
Drink less alcohol.
Spending some time or even a full night at a lower elevation (ex. Denver, which is at 5280 ft) before heading up to Vail will help you acclimate to the elevation better. Our wedding venue is at 9350 ft.