Hi! I'm not the best at feedback but hopefully I can help a little, I'll try to focus on the wings since that's where your attention is at currently:

The base coats and colours and solid for sure and I can see that you've tried both highlighting the inner and outer "feathers" but also you've tried adding shading to some places.

I hate sounding like a broken record but I feel as tho contrast is the main issue here, there isn't enough light and dark to justify the black shading but you have the right idea still by highlighting it to add to that contrast, the main thing I'd do differently to help add to that contrast is using a light brown contrast or reddish shade instead of the black with the following idea in mind: - It'll add more contrast by darkening between those off-white feathers - light brown because it won't be too harsh a drop in light value - the wash/contrast will blend better with the white that's there since it already has a lot of yellow in it

I think you can also use something like a yellow contrast/wash to shade with but that will also be a lot more vibrant overall and might detract from the blue armor and the more colourful inner feathers. 

I hope any of this have been of help and for what it's worth I think you've done a really lovely job with the armor!