Sorry for the late response. Okay here we go. I want to make this as clear and concise as humanly possible bear with me. Ahem.
The composition, itself, is a little centered and usually stale and boring. It easily gets dismissed if there isn't enough information on page. Maybe turning the canvas a bit or camera angle can lend a bit of a dynamic, this doesn't mean that you should do it. It's merely a suggestion. I think it is important that you make final decisions in the end. There are other alternatives to approach; that's just a couple though. Perspective is off everywhere. Remember there is a definite top bottom side to side of things. It usually depends on where eye is centered. I like to think x and y axis. Having a horizon line and using vanishing points can aid you in solving it easier. It's sort of like training wheels on a bike till you get better at aiming. I do think you have a general idea of it though, but i do feel it can be polished. Design on the door can be a bit more interesting in my humble opinion. This can add a bit of interest to location of where she is delivering cookies. Compton versus, nice surburbs to, rich neighborhood, 15th century, dark ages, church, etc. Pay close attention to front of doorways, outside coming in. There is usually a bit of a drop off at front of doors which can also lend some help to storytelling. You can add little miscellaneous things like a thing to hang your coat, hat, a little table, key rack, carpet, shoes, light switch, plants, things that you would see at the front door to add some story to a house. Us good illustrators like to see little things like that, which is effective and helps us relate to painting better. It doesn't need to be over the top detailed but enough information for people to at least get it. Maybe a cockroach, haha, crawling on the floor. Whatever gets people to say wait a minute... I really don't want to tear down on cartoony nature of piece because I think it can pass. If you were going for more realistic approach, then reference is the way to go. Study and practice anatomy and proportion. Later on you can explore those areas a bit more. But, knowing and showing how things work with figures or creature, giving it a function, usually adds to the jazziness of a character, on a side note. You can add another character there as well to interact with girl giving cookies. It probably wouldn't work though since girl scout is main focus. It is always better to plan first. I am thinking about why the door is open? who opened it? It's good to ask those questions. The monochromatic color palette works since glow from box is dominating but adding subtle warmer hues can add some variation to color palette. Warm shadows against cool lighting would be effective here. It's nice to see that worked out into paintings. You can possibly do it in flesh since it is translucent and get away with it. It's called sub-surface scattering. I would have to show you that though haha. That is a bit tough to explain how to do it, since we are visual. It also must be consistent throughout painting and not over done or it will look like it is, well, over done. If it is going to be intentional be intentional with it. The space behind the girl scout could use a bit of love. Again, this will give me a better sense of location. Overall just needs more added to it. I really feel this piece has potential, and could be pushed a lot further. Don't feel defeated though. Just take what I've said and apply it to this if you want to further develop this one. But, do experiment. It's good to run into accidents to use in piece later on. Wish I had time to do a paintover so I can show you what I mean, but don't have much time to do that as I have to finish up a commission. I've been slacking.
Other thoughts to help you along:
I think it is very important to get down a sketch, and do another and another. Plan first. Look up reference, enough to get you started. You can also do studies of what you will be painting in scene as well. It helps to know the subject matter painted in illustrations better before going into the final. If you have a decent camera you can use that as well to take some stock photography of your own. All you need is good amount of information to work from to help guide you to get forms painted correctly. The less guess work you have to do, the better. Do look up tutorials and other things to get a better sense of what is going on. There are plenty of digital tutorials floating around about how to do stuff. Just paint and draw a lot and enjoy the process. You get what you put into it. Again, don't let contests dictate anything. They are fickle in nature as you don't know what to expect. Hope this bit helps you along. My thoughts on your piece and good luck on your future endeavors. Heck you may be the next Dave Rapoza or something of the sort. Keep painting, again I reiterate. Later.
Hey I really appreciate the time you put into this. Thanks a lot for the pointers. If you could see how one-dimensional my work was 8 months ago, you'd see how far I've come! haha I get the gist of perspective but I don't have much experience putting it into my work. The school I go to doesn't really teach me things like that, so my work has almost been at a standstill for the past 3 years. I now think very conceptually and can talk for days about mine and others' works but am having to catch up with the techniques(even simple stuff like basic composition and COLOR THEORY - I know, it baffles me too). So in other words, I really liked my concept, but personally thought the piece could've still been stronger. I know there could be a lot more to the piece that I'm just not considering; not because I'm lazy, but because I don't know how to execute it. Things like dynamic camera angles and camera lenses are a hard thing to grasp but I would LOVE to use these techniques in my work. I'd really like to see some of your work to maybe better understand some of the suggestions you gave me. I would say my work has always been, and will probably always be, cartoony. I've tried so hard to make it more realistic, but even the closest I get to realism is still slightly cartoony. I've stopped fighting it.
Anyways, know that I took every word you've given me as a constructive piece of criticism. If art school has taught me anything, it's to never think you can't get better and how to receive a crit. With that being said, I thank you again. Back to the drawing board!