If we are doing a list, I'd put it in this order.

1. Ride 30 hours per week
2. Body fat under 10%
3. Aero bars with a proper fitting
4. Skin suit
5. Aero helmet
6. Aero booties
7. Aero wheels
8. Brifters with 10/11 in the rear
9. Light/aero frame

In a race with 100 people, if you do #1, I can guarantee a top 5 finish. If you do #9, I can guanantee a top 100 finish.