Coaaal, I’m working in Photoshop and I’m setting the layer options for the color layer to ‘color’. PM me if you need some Photoshop tips.
Setting the layer to color will allow you to paint with whatever color you want and it will maintain most of the value work from previous layers. I’m also painting with 100% opacity on the brush. Where that deviates is a setting on the brush to control opacity with pen pressure.
After I have the basic colors down I’m creating a new ‘normal’ layer above the color. There I use the eye dropper to grab a color/value combination and start painting the finer details.
Let me know if any of this seems vague and I’ll expand a bit, or even create a more thorough tutorial to illustrate my point.