How can you know if it's a good looking yukky stage or a bad looking one? How can you know that it's going to lead you somewhere good ot that you're just wasting your time?
On the one hand, you're right that if there are serious, major composition errors in a picture, no amount of "rendering" will compensate. That's one reason why thumbnailing and preliminary value/color sketches are a part of so many artists' methods. However, it's also true that good pictures go through the unfinished stages, and you can't let yourself get too psyched out by that and give up.
However, that leaves the question: how do I know whether any given image has those fundamental problems that require a more severe reworking? For that, there are a few things to consider:
Could another person look at this image and tell roughly what's going on? This question applies more to very dynamic images where a lot is going on and there's not a single well-framed focus for the reader's attention. This question applies to "all over the place" pictures. The example you posted is NOT that sort of image, and it seems very clear to me what is happening in your picture.
Is there a clear establishment of values, based on a believable lighting scheme? The image you posted seems fairly well-thought-out in lighting: there are two light sources, one warm (the lamp) and one cool (the outside light coming in through the door). The characters and the space appear to be lit by those light sources, and nothing looks too horribly wrong given the lighting set up you've chosen. There are some good details that help the believability, like the cast shadows from the picture frames in the background.
- Are the colors harmonious and within a unified scheme? Your sample image is very strong in this regard. The palette is within a nice range of warm, related hues. The cooler outlying colors (the blue of the outdoor light, the green of the chair) are less saturated and pulled more towards the neutral center of the color wheel, which keeps them in harmony with the dominant palette. You don't have any clashing, vibrating colors that stick out horribly.
Given that your image satisfies those three questions pretty well, I think you are doing OK. The next step in that case is to get more refined in terms of values. You could stand to push some of your darks darker in the corners (occlusion). Any place where something is touching something else, it's hard for light to get in. That's the source of a lot of the "lines" we see in the world, like where people's lips touch, or where a foot meets the ground. In your image, that includes the places where the mouse's head/shoulders touch the back of the chair. You've got a perfect one right on the bottom of the lamp's base. That small, intense shadow is a perfect example of an occlusion shadow. Those tend to do a lot of work in communicating the believability of the lighting.
I'd also suggest you refine your edges and transitions. Right now, you have a lot of soft edges/transitions, even in places that are hard corners. For example, the door is painted very softly, but the plane changes on that object should be firmer. Same thing with the armchair: the front plane of the chair should be more defined. Soft, airbrushy edges everywhere have a tendency to look messy and soupy. The firmer edges you already have, like the tops of the mice's heads against the dark background, are the strongest and clearest parts of the image. As you bring more definition to the interior of each character (like where the newspaper meets the mouse's red shirt; or where the seated mouse's head meets the other's dress), it will improve the overall image.
It's possible to get really fussy with all these things, but given the drawing style, you can afford be restrained in how far you push your form rendering. Sometimes you can have very well-painted lighting and form, but it looks weird because the painting style doesn't fit the aesthetic of the drawing.
There are some perspective issues in your drawing, but they're minor -- nothing that really disrupts the reality of the image or makes me think something is dramatically wrong. But for what it's worth, look at the degrees of the ellipses of your table, lamp base, lamp shade, etc. The rug is a very wide-open ellipse, but the lamp base is much thinner. If they're both on the same plane, and both in roughly the same place, they should have similar degrees. But I just want to re-emphasize, I don't think these things are make-or-break to your image as a whole. The big picture is very strong.
Overall, I think you don't need to be too hard on yourself and throw anything away. You're closer than you think!