I've been into ASE 300+ times in the CRJ-700.

If you've never been, go VFR. Be fully configured abeam Red Table or configure while passing DBL if flying over it. Try to do a constant angle descent as best you can. Be prepared for a 10 knot TW landing on 15. If you have to reject the landing after the missed approach point climb at v2, wait until .7 DME south of the airport then LEFT turn to get on the loc bc. The runway is narrower than standard and uphill, so the illusion is that you are high. Don't go at night if you've never been. Watch for windsear on short final.
On departure stay over the low terrain. 3.7DME left 270. If you lose an engine do not return to Aspen.
Don't be afraid to say no. Aspen is NOT a 365 day a year airport. If you have microsoft flight sim or something similar, practice flying around there. Play around with google earth if you don't have the game.