Originally Posted by dirtbikedude
Some other considerations, what bike are you using?
Do you lower the seat before descendeing?
Do you hold your breath when going through technical sections (this will cause you to get very tired, very quickly and most riders are not aware they are holding their breath)?
Is your center of gravity to high? You should not be in an upwright position. Your butt should be back and down, elbows bent outwards(not down) and your chest/shoulders should be low.
Eyes. Eyes should always be looking ahead and
NOT at the ground a few feet in front of you. The faster you go, the farther you look.
If you have to use the brakes, do it before a turn and not while turning.

I'm using a Santa Cruz Blur. Kick ass bike, I love it. It's got a low center of gravity.
Sometimes I lower my seat for descending, but in my area, terrain is rolling, so I rarely get a long enough section of downhill to slam my saddle down.
I don't hold my breath... should I? I do sometimes stick my tongue out in concentration. (I know, bad idea.)
Not sure about me being back and down far enough... I think I am, but how do I know for sure?
Eyes... I definitely need to work on this one. I catch myself looking right in front of my stupid wheel all the freakin' time!!