I've never really made a guide like this before I hope it helps! There is gonna be p.2 in a bit! I ran out of room-
Edit: I added steps down in desc here
Make sure theres a curve in the top of the wing,
More straighter (longer?) the more extended the wing is
Add feather details along the bottom of the wing! That usually varies sometimes
Follow the pattern I wrote
Add more details and feathers in the center of the wing, I usually just follow the bottom of the wing pattern but with more close patterns
Also use refrences those help a ton