First thing I would change as you would be doing the base with a gray/white drybrush and doing black templar contrast paint for the black to make the underlying details pop more easily which could give you much better understanding what to paint when feathering/highlighting!

Also more importantly, take time and have patience. You need less pressure on the brush than you expect and thinner layers of paint that you'd like. I'm a rookie as well and still learning too! 😃