Oh, good points! Ummm, I really don't know on outfit. I was just starting to do an image search for "Valkyrie outfit". It's mostly just... armor of some kind, plus winged helmet. I can't tell if it would be better for me to try and link some of the results of this image search, or since I really don't know what is easier or harder to draw, leave it up to you and let you pick....
Helmet is key! She has to be wearing a winged helmet. Let me see about finding another picture of her though without sunglasses. I got my brother to come up for a visit and help with photos because at one point Moi was going to draw her too (I just never actually got her the references), so I know there's a couple photos around somewhere.
Just a minute! I might have to call him, but I'll edit in links as soon as I find them!
Okay, here you can see her face better:
Valkyrie outfits....
Here's an amazing helmet someone on Pinterest made:
follow this link to image
I don't know, you make pretty awesome outfits, so I almost trust your instincts more than internet image searches. I'll keep looking though.