Sure thing, I'll try my best! So, I'll first touch on values, as, that seems to me to be the thing that will help the most, and the advice I can most confidently give. Analysing your piece, it seems to me like there's a problem in the intentionality of the contrast. Contrast is THE BEST tool you have on your disposal to guide the viewer to where you want their eyes to go. We are naturally drawn to areas of higher contrast, but in this case, there's not enough of it to really guide the viewer. As an example take the top-right panel. The area of highest contrast in this is the cabinet, which is something rather secondary to the piece. You want the viewer to focus on the characters speaking, so you have several options: a) you can alter the values of the surrounding pieces to more naturally guide the viewer to the center (making a darker floor, more vibrant shirts), or b) add light to illuminate the areas of focus and darken the areas you don't think are as important. Having a solid understanding of how light works will allow you to naturally create more striking panels, and will elevate your pieces tremendously. As it stands, this current WIP is still too flat (evenly lit) to fully judge how things will evolve when you add lighting to it. What I suggest is you start thinking in thumbnails (you can search for examples on Youtube), which are basically small, rough, value sketches, just to ideate on what looks good, without wasting too much time, or becoming too attached to it. Then, after you do some thumbnails, and see something that looks really good, that's when you commit to it, and start thinking more about lines, and go from there. In terms of colour, I think it's best to just base yourself on a greyscale value painting, and then add a color layer on top of that to see what works best. Hope this helps!