Hey!, im really liking your sprites, tho, i have some ideas that could help you execute it a lilī better.
- First of all, focus on the anatomy and stance of the knight, lets forget about colours, shading and details for a while.
a) Try to draw his human figure without armor first, so you can have a better understading on proportions, and anatomy in general, right now the lenght from the the waist up, doesnt match the waist up for instance.
b) The pose feels very unnatural, specially the waist/leg area
-Once you have done that, focus use the colours to bring shape and volume to it, for now, just limit yourself to only 2 colours for the entire pic (make sure theres a real contrast between them), dont forget how everything interacts with each other.
a) You have some shadows applied already, like in the waist area, but others you dont have any, for instance, below the head (neck area) below the shoulder pads, knee pads, etc
-When you feel comfortable with it, you can start adding "big details" like the armor, gloves, etc
a) Again, make use of the techniques above
-Now, start replacing those 2 colours in general, with 2 contrasting colours per area
a) For instance, have a light gray, and dark gray applied to the armor, taking as a base the volume that you already applied to the model.
-Finally, start adding a third colour, wich can act as a midtone or shade, and wip out every little detail you might have.
Cheers.