hey anon! for coloring, sometimes i do look back at my older art if i like how the colors turned out for that piece but i think i mostly try to see what looks nice if i can depending on the mood i'm going for (ex. saturated, warm, cool, soft). it doesn't appear when i draw on stream for some reason but i often play around with the saturation and hue slider in order to see what looks right to me in case the colors i picked isn't exactly what i'm going for. sometimes i do color tests on a different canvas before i start coloring on the final piece which can be helpful especially when working on a detailed piece so i don't have to color over and over if i don't like it. i think when i'm coloring a character for the first time, i usually do a color test to see what palette looks nice to me. as a little example, i remember i used to have a hard time coloring victor because i wasn't used to coloring red and yellows together and would try to put together a palette for him and over time it's been a little easier to figure out the more i draw him. sorry if i didn't quite answer your question, feel free to let me know if i didn't and i'll do my best to answer but thank you so much for the ask<3