Nice work so far. I think the pose is really cool but you can still work on it. Maybe try raising the arms more. If you have a friend and a phone with a camera, do the pose yourself and use that as reference. For the composition, it seems like your following the golden spiral which is a good thing. I think adding a bit more elements to the comp and help push it further. I really believe you should get some reference for the armor and anatomy. As far as the values go, I feel you need a better understand of your own light set up. To me it looks as if you have a back top light which is giving your character a rim light, a front light coming form the viewer and then you have to think of the bounce light. I recommend not using 100% blacks and whites and instead use the other values in the value range. I say this because if you ever want something to seem brighter for example, it won't look bright due to you already having a 100% white already. The contrast in values could break. My last recommendation is to focus on the head area more. Unless you want you main focus somewhere else, having the focal point being the head is a safe and good bet. I didn't know this night had a face at first.
Anyway I hope this helps a bit more. Best of luck.
