I've done some spriting awhile ago but I'm creating a sprite for fun right now,
This is what I've done so far, I'm having a little trouble doing the chest plate atm
Any help is appreciated!
start with the proportions then sprite character over it, you already have far too many colours and jaggies all over the legs.
Those colors on the armor doesn't show depth or shine at all. Try touching it up. Look at a picture reference.
You have way too many colours, you probably only need 2 or 3 grey shades, and also you should have some white for highlights, as metal is very shiny. Here, I did an edit for you to show you:
This probably isn't exactly right, as I'm not really an expert on shading metal, but hopefully it helps you out.
Finally, you don't have to do this, but you may want to consider not using black outlines, and instead just a dark shade of the colour it is surrounding, because pure black stands out a lot and is very visible, which you don't always want, especially if you're trying to make a sprite look realistic.
good luck