Bicycle Tutor

First of all hello and wow what a great forum!
Secondly, I have an old GT Avalanche 1.0 disc circa 2001 and it has had a lot of use and abuse. I keep it well maintained and it looks almost brand new. Now on to the point of this post....
I am having problems going into my smaller gears, sometimes my trigger shifter shifts correctly and quickly, but sometimes I have to push the trigger shifter as far as it will go (its endpoint) to get it to shift, kinda like it is soft, but it does shift. I have found that if I put upward pressure on the trigger shifter while shifting into a smaller gear it will shift normally. Going into big gears is a non issue.
I hope this makes sense...
Thanks in advance,
Rich

Have you tried cleaning the shifter mechanism, they can gum up a bit and start to feel a bit stodgy, take a look at Alex's video: http://bicycletutor.com/rapid-fire-shifters/

Also, check that the cable runs as smoothly as possible in the cable outer as this effects how "snappy" indexed gears feel.

Cleaned up under the dust cover and that looks/feels like it did the trick. Thanks xerxes! And Thanks Alex for the vid!