Well, I start with an image that I know exactly what all the colors should look like.
Normally I turn all the color pots down all the way, then turn the brightness up until I see a white haze, then back it off until the haze just barely goes away. Then I turn up the red bias pot all the way until I get a red background, then back it off until the background just barely goes black again - but you can still see the red images on the screen. I do the same with the green and blue. Then I adjust the red and green drive pots (and blue if applicable) to get a nice bright picture. The last adjustment is contrast if the monitor has that.
Sometimes I have to adjust the brightness down or up a bit once the colors are asjusted.
And watch anything that should be white. if it has a slight tint, then that color needs to be turned down a bit, or another color needs to be turned up...