The following is the singlemost helpful bit of advice I ever got about painting. If I could think of one key to successful eye-to-painting translation, this would be it, so read on...
In the fall of 1988 I was a sophomore at the Maryland Institute (MICA), in Baltimore, Maryland. I could draw. I understood color and how to mix, and I'd been painting in oils and acrylics for a number of years (with middling success). I entered (the Mighty!) Mark Karnes' "Figure & Landscape" class and was really depressed about the two horrifically messy landscape paintings I made after our slide lecture. At the end of the day we had a crit when (for the first of many times) Karnes, in his Kermit the Frog-like voice, started talking about "Little pieces of light and color" and their "particularities".
When you're painting you look at your scene, and pick a place to start. You carefully mix a color that corresponds to what you see for that patch. You look right next to the patch in your scene from which you made your first decision, and determine: its color, whether it's lighter or darker than that patch, and whether it's warmer or cooler than that patch. Mix that color decision up on your palette, and lay it in right next to the last patch. Keep working "What goes next to the previous patch" like this until your painting is done.
(BTW: All perceived color is relational. "Color", defined in a general sense, refers to all aspects [hue, sat, value, and relative temperature] of a defined, quantum patch of perceived light).
If you consciously and carefully apply this method you will be amazed at how your paintings start to truly reflect your visual experience, which is what good paintings do. Even if you're working out of your head, as we all do sometimes, asking those three questions will lead you towards more deliberate and interesting decision-making.
This has been your Million Dollar Post.
Yours in the fabled Karnes-ology,
p.s. Karnes did one of the hands-down, best paintings I've ever seen. I'll see if I can get a hold of a repro. It was a still life of several of those yellow #2 pencils, but with the *green* erasers. (It was around the same time as the golf ball still life below.) It was one of the most exciting paintings I've ever seen because it was so unassumingly beautiful, yet shockingly well perceived and translated...and ballsy. (You could've put this little painting next to one of Francis Bacon's Screaming Pope series--the loudest paintings I've ever seen), and it would've been equal to the task. (Really.) Also, it made me aware of green erasered pencils ever after. Years later, now, whenever I go into a store I see if I can find some!