Those articles are good, but there's one thing I will add. Most people think trimming is a one time deal, but this is simply not so. I have airplanes many years old that I still tweak a little here and there just to get that seemingly elusive 'perfect' feel. Most people don't realize just how misadjusted their airplanes are until they fly something that's been painstakingly set up. Even my old trainer feels really 'locked in' after I took the time to make those almost imperceptably small adjustments.