If it's the very very first time you're doing this, I like your take on it.
Are you trying to stay true to the NES, however, you're supposed to be limited to only three colors (which is why Simon was so simple back then).
If this is for homebrew or just to 'test your skills' with a still retro version but not really an NES-centric version, then I like your armor shading color. The hair looks like the box art and so does the super-tanned orange, though from far away, they make Simon look wierd.
I'm not a fan of the bright yellow. I realize that the shoulderpads and kneepads in the boxart had gold accents but they just make the sprite look a bit too 'busy'.
Keep at it, though! You get better each time you attempt at it and people here will help you.