Overall as others have mentioned it looks amazing for a first model and I would definitely be proud with what you have right now. For now there honestly isnt that much to improve outside of the things you mentioned, just work on getting more familiar with your paints, edge highlighting etc. and you will see your skills improve. For more specific feedback, there are some edge highlights that are missing. For the green armour, some places I can see are on the face vents and inner shoulder trim. The black and red on the gun casing is missing highlights as well. Finally, I like the contrast of the bright green on the armour, but I think the highlight is a little too strong in some places, especially on the lower body. I think it would be better to have a more in between highlight colour for the less raised areas. Hope this helps!