You're using two colours for your outline: Pure black for the hair and what looks like the darkest shade of skin for the armor's outline. Even if you don't want to use an outline color from an FE game. Try to stick to one color at least.
Also, you're using the outline colour as the third shade for your hair. Oftentimes, this can be good for black hair. But your sprite's hair is more of a blue shade. You may consider something near the darkest shade used in Colm's hair instead.
As for the hair itself. You generally don't want to use the darkest shade for the hair too much, as it tends to stand out quite a bit. At most, keep the darkest shade in 1 pixel lines and use the 2nd darkest shade to define the locks of hair. The lines are bit choppy, so try to practice tapering the shades as well.
His pecs are angled slightly different from the body so you may consider trying to add more cloth under the left shoulderplate (our PoV)
But overall, it's a fair attempt at custom spriting for the first time. Your sketches are quite nice, though.