Looking sweet overall mate! I love the hues used in the background, but I think the saturation could be toned up and the background somehow made to be more fitting with the character's stance. You have a good idea of muscles in the body and forms of anatomy, however, you have to brush up on proportions and some slight readjusting of certain limbs. The right arm seems to be a bit to low and possibly too wide for the character. The arms and hands are a bit too large as well. Just experiment with a transform tool until it looks right to help you get an idea of what I'm talking about. Also, don't feel like you're cheating by using references! They can be helpful in getting your first bearings of proportions, and I've even used them to polish up my anatomy. I still kind suck, but anyways, another proportion you might want to watch out for is shoulder width that is dependent on gender. Females have narrower shoulders, and guys have wider ones, research the ratios and look at photos and you'll start noticing this pattern. Try to clean up, blend, and sharpen your shadows. A lot of the surfaces in this piece are curved and don't have hard edges to their shading. This goes for the hair as well for using sharp shading. The straight hair of the fairy, in mind mind, shouldn't be straight, and in drawing doesn't look natural. Make it flow or have fun styling it! Hair that long shouldn't be that straight unless a whole bunch of logic, and hair gel, is holding it up!
I think that's all for now, because if I say anything else, it'll be an overload! So, do't feel scared by all of this, I go through this same thought process when I do my drawings. Just as long as your read this through and during drawings think about these little things every once in a while you'll get better. Experiment, and just try to apply things every once in a while. In essence, don't overload yourself. It takes time, so keep on drawing mate! If you have any questions feel free to ask, I know you're new around here, and there's a scouting system you'll ask questions about, so, if you need a friendly face to help out, you can PM me. So, welcome to NG!