Amy Rouge Pixel Art

[Vipershark]

The way you did those outlines is one of my biggest spriting pet peeves ever and they make me really angry.
Every single person who does large PAs like that (well, most of them are traces which this isn't so I'll give you some credit there) does colored outlines that way and it just looks so bad and I hate it and AUGH

Sorry, nothing personal against you, I just REALLY hate when people color lines like that.

First and foremost, some of your lines are jaggy and you need AA in general to smooth everything out.
As far as fixing the colors, your outlines need to change color with the highlights. Your outline color shouldn't be the same color on a bright white as it is on a dark grey. Look at the hammer. The yellow outline is all one color and it just sticks out really bad. You should be looking at the hammer as an object, not some lines that have color in them.