/ic/ - Artwork/Critique

Id like to hear any and all input i can get on me being stuck with painting.

When drawing the thing that clicked, the thing that made me instantly be able to recognize my mistakes and know what to study was finally "thinking in forms" as in 3D.

When painting i dont even know where to begin to understand the basics of how i could approach painting something realistic / believable from imagination.
When copying a reference im doing just that copying, i cant make sense of the colours and values i am seeing.

Pics related are an estimate on where i am right now (dont mind me pussing out on face and hands + feet, i even struggle with painting a skin coloured sphere right now).
The upper picture is from reference (dont know if 3dcg flatchested gets me banned here so censored), the bottom one is what my little knowledge of painting amounts to without a reference.

If anyone has an idea of what i am talking about and has some suggestions / exercises / tutorials / books that might help me itd be greatly appreciated.