I'm actually gonna address this in depth with my blog (
http://www.drumlessonsportland.com/ ) here before too long. I tend towards a lot of mental chatter myself, and have really struggled with it. For a couple of years now it's been a hobby of mine to ask famous musicians what their coping strategies are. There are 2 answers that nearly everyone gives. Everyone knows exactly what I'm asking, w/o clarification, and almost EVERYONE gives some form of these 2 answers.
(1) ----A----- Remember that nobody cares about the drummer if you mess up. Often, people remember a specific story that happened to them that really drives this home for them, individually. You gotta get your own story. You cannot do this on w/o it. You cannot take any one else's word for it. That will not work.
-----B----- You get to play music. It is a wonderful opportunity. (this one, imo is dangerous, because it invites the oh-so-ironic 'I need to do well' voice to come in. But it can work wonders. Again, especially with a strong personal experience/memory tied to it.
(2) Distract yourself with sensory stimuli. There are a couple that work great for me. One is to attend the touch of the stick in my hand - so that I feel how the stick rings like a bell with every stroke. Another one that works amazingly well is to attend to my feeling of being balanced/centered. These are hard to describe, but its a lot like meditation. Sometimes I listen to the timbre change over time in the reverberation of the snare (I've had students suddenly acquire shockingly good time at extremely slow tempos with this method, I learned it from Hal Galper
http://www.halgalper.com/ ... (
this does not work with electronic drums!)). Point Meditation is another one, where you pick a point and stare at it, fill up your mind with that one point. Doing this sort of thing allows you to step outside yourself and to let that nasty chatter go. You cannot 'control' this chatter. You cannot will it away, force it into submission. You have to desire to do something else instead.
To put these another way, it means
(1) Connect with what you are doing. Music is not notes, it is not impressing people, it is not trying to get a better gig. Its the old joke - if you aren't present, where are you?
(2) Connect with how it feels to play music.
Esperanza Spalding gave neat 3rd answer, btw - she said she tells her band mates that she's having a band day, and that they should help her out. Maybe this is only something you can do if you're the bandleader, tho !!