I've read a lot of Sports Psychology recently, and the Omly thing that works seems to be your basic behaviorist "do it and it will change" techniques. First, some reading:
"Sports Psyching", Thomas Tutko & Umberto Tosi
"Skiing Out of Your Mind", Loudis et al
"Smart Skiing", Dennis J. Selder
"Psyched to Win", Robt. M. Nideffer (if you only buy one, this is it, in print, at B&N, and the guy practically invented the field. Nideffer is also an Aikidoist, and manages to combine science with some spirituality).
The most obvious example of a behaviorist cue is many racer's "pole-click" as they enter the gate. It is a Pavlovian cue to enter their ready state. However, getting to the cue, what it means and how it works consistently, takes practice--those dogs didn't salivate the first time, but only after repititon. So, you can om all you want, but you have to practice--train yourself--building the association into a meaningful behavior cue.
Another is learning your optimal state of arousal (please, no comments about big sticks, pole plants, etc.) and learning to achieve and manipulate it. Again, look at racers at the start. Bode's a mellow fellow, cool and joking, but inside his pulse is like 150. Hermann's a teeth gritting, focused monster. They've each learned what works for them. What doesn't work is being too pumped or not pumped enough. You must study your best performances, identify your mental state, and find ways of achieving that mental state on command. "Tick Tick".
I achieved a degree of release when I realized that some days I just wasn't going to get to the zone no matter what I did. There were just too many other things going on--fight with the wife, worries at work, whatever--to even try to reach maximum performance. Since I'd driven to the mtn., I'd take some turns and work on some skill, but no trips to the no-fall zone today, for sure. Again, you'll see racers do the same thing. They recognize that today just ain't gonna be right, and scratch before they hurt themselves.
Finally, remember Lance's advice: "motivation won't take you very far if you haven't got the legs." I gain confidence from conditioning, and skills from drills. You can only choke when you can perform in the first place.
Good Luck! And remember, Einstein was right: the faster you go, the slower you age.