to be honest i think the highlights on the carapace are in the wrong place. especially on the legs, it looks like on the deepest groves its the brightest.
the paint looks rather thick, try thinning it down with a bit of tap water (about a 1:1 ratio) and apply more, thinner coats and you will see you will get a more even coat of paint.
since nids are organic, you can achieve a good look with drybrushing and washing
there are a lot of tutorials on how to paint nids effectively, try looking at those.
its really not a bad model for a first attempt, but im sure you can improve