This picture us a bit dark, but my 2 cents is that you may be over doing the highlights. Use white sparingly and only on the parts of the mini that would get direct light. Very sparingly on an assassin that would be trying to stay out of the light. Instead of straight white use a lighter color of base color. That is to say, base color plus white. I would guess at maybe 1 base color + 2,3 or maybe 4 white - it really varies on the effect you are looking for.
Another thing, use a bit more water in your paint. It looks a bit thick on this mini.
Keep it at it. Your doing pretty well for just starting. As long as it's fun for you, your skills will progress at pace.