Meysam- for mental prep before a race I definitely advocate that you have the same prerace routine. Make it ingrained so that it is second nature. That way it brings regularity to your meet experience and gives you one less thing to worry about. For reaction time, that is tricky because I assume you feel like you are getting left in the blocks? If you have poor start mechanics, even if you apply force before everyone else you will still feel like you were left behind. It might not be a reaction problem and might be more of a coordinating power problem.
albtensai- I focus on different things at different times during the race. During the first 15m of the race I focus on a strong pushing backward motion, from 15-40 or so, I focus on a hard hitting downward motion. From 40-80 its more of a whipping feeling from the glute but still with a focus on hitting down and under me, for the last 20 I focus on picking up my knees quickly.
It may seem like alot, but its fairly easy after a bit of practice. I started doing this after hearing Seagrave talk about using different cues to help prevent CNS fatigue in the 100.