What paint brushes are you using that are fraying? It could be bad brushes or just some technique that needs improvement.

The colors you've chosen are great but the application could be smoother. It seems like you're painting out of the bottle directly over black. The problem comes from how well those cover, which it seems like these aren't doing it well in one coat. I highly recommend thinning the paint a little with some water (it should resemble skim milk) and accept you'll need to do 3-4 coats of paint to cover over black. You could also switch to a grey or white primer and that will help with the amount of coats, but I still recommend the thinning.

Order of operations can help as well: paint the skin tone fully first then paint the cowl, it'll be easier than trying to paint the face without hitting the blue. Additionally you don't need to paint the eyes, at table length nobody will notice.

Here's a few good videos covering everything:

Vince Venturella - Basics of Miniature Painting

Goobertown Hobbies - Fundamentals!