Avoid light sources in your line of sight when coloring. backlighting your monitor is a great way to light "out of sight." I'm using 4 LED lights that I hid behind the monitor stands and speakers to keep them out...
When setting up your coloring environment, try to pick a neutral wall color (like a 50% gray) to manage color influences. For my office, I used a photo gray card to match the color. When coloring, you want to be...