Any idea on what i should add to this work? It's just a roughing.
I've not did graphic in a while.

Color would be a dominate feature you could enhance and make the main element.

Such as defining some depth and rhythm with some warm and cold colors parallel.

Hope this can help. Best of luck to you can your piece.

Looks very "Retro" If you made it that way I would say you did a great job. Really like it, if that was the approach.