I don't want to suggest any colors because I'm stupid with them xP But I'd like to advise fixing the girl's arms a bit. I can't really put my finger on it... But they look odd xP I'm sorry I can't be of much help~

Good luck on this~ It looks beautiful

I always enjoy an open invitation for constructive criticism.

Actually, there's not much to criticize, just two little things that are bugging me, and a couple of others that I'm just going to point out because you asked.

The first thing that bothers me is the girl's eye that gets hidden by the glare of her glasses. It seems like it shouldn't actually be hidden or something. Unfortunately, I can't really offer good advice for making it look right. I always have trouble drawing eyes behind glasses myself. The best I can suggest is just drawing the eye like the glasses weren't there and then deciding what to do.

The other thing that bothers me is the position of the guy's wing. Luckily, it's easier to spot how I would correct that. Moving the wing a bit down and to the right. I always imagine wings growing from shoulder blades, and from where this one is, I'd say it seems to be growing from the guy's neck. Draw it going more up than out if you don't want to lose it off the edge of the page.

Since everyone seems so adamant that this should be a wallpaper, I say you use wallpaper proportions for the final, and let people use it as such if they like.

As for colors, I'm picturing light colors for the girl and darker, muted colors for the guy. (I know it's a bit cliche, but that's how I see it.) Specifically, I'd go with a charcoal grey for the guy's shirt and make the skull white with a black outline. I might also add some red to the skull outline and perhaps to the watch and headphones as an accent color. I would make the girl's shirt a light color because from the sketch, it seems to be made of a very light weight material and light weight materials always seem to come in light colors. I was going to suggest pink, but if you use red on the guy, I think I'd avoid pink on the girl. Light blue or lavender would probably work well. You could pick a darker version of the color for the tie and use the same color for the skirt to keep the outfit tied together. You might want to use the same color for the stripes in the shirt, but I might consider leaving them out entirely, if you can't come up with a good color for them.

Finally, I'd consider moving the girl in front of the guy because she seems like she should be leaning against him a bit. (This is also partially because I just can't think of a good color for the guy's pants/belt. :-P ) Of course, it might make more sense to leave things as the are now. The way they stand now, the girl's gaze looks straight at the guy. If she was in from of him, she wouldn't be able to see him just by looking up at that. Alright, I'll stop now before I over analyze this sketch too much.

Hope that gives you some good ideas!

well for starters you should ink it, color it then make it a wallpaper...

I fink maybe for the colour you could outta ideas in my head try maybe a like blue and green top for the guy.Meaning blue chest green arms?

I like the emptiness to the left, very wallpaper like. The paper color is nice too. Maybe just add one other color to the whole picture, i think that would make it pop a bit more. Other than that, i can't complaine, it really good.