The answer in a perfect world is to spend time sleeping at elevation.

You want to sleep high, and train low.

Living at altitude gives an adaptive effect to the altitude, such as increasing hemogobin. The tradeoff, however, is that there's less oxygen to train at high altitude, so it's harder to train yourself to put out power.

So training at lower altitude you can push harder, and raise your FTP, but you're not acclimating to altitude.

Hence the live high, train low theory.

As a practical matter unless, you're going to drive from Denver to Leadville everyday, or sleep in an altitude tent, you just have to trian as much as possible aimed at increasing your FTP, specifically your w/kg.

Thus, there's really nothing you'd do different training other than working on getting stronger, knowing that the altitude will take a percentage of your strength.