Im gonna take a different aproach then most of the other responses here. I think most of the definitions of AF your getting are a kind of redefined AM definition.
Some of the aspects are similar, take leadership or independance (not looking for validation). However, when i think AF (dont laff about this im serious), think of a grandmother figure. The central women in a family. They have opinions of thier own, they lead the other women in the family.
What makes them different then an AM?
They dont display characteristics that show survival value, but instead show replication value. An AF should be receptive, caring, yet still possess an independance and sence of self.
Im also gonna say that you will rarely see a AF because in alot of ways it may be counter productive to them displaying RV (reproductive value). Im not saying its not possible, but for most women, they are hardwired essentially to not be "Alpha" personalities.
As for what type of women i like to be aproached by, it is probably almost in line with what a women wants.
I dont like women who show intrest up front. I like to "work" for that intrest the same way women want to. I dont like women commenting on my physical appearence(Erin

), looks, etc. I do not consider these my best assets and if that is all the women is intrested in me for then im not intrested.
What i do like in a womens aproach once again is the same. I like to be aproached by socailly outgoing girls who come accross as just friendly. Talkative, playful and maybe a little flirtacious.
I like many other guys, aproach women based first on looks (we all have our standards), but i aproach to get a feel for thier personality...and if thats not upto my standards all the good looks in the world arent enough to keep me intrested. I analyze a womens personality the same way when they aproach me, and if thier personality doesnt intrest me i will blow them off.
Hope this helps, id feel like i was giving weapons to "the enemy", but as far as im concerned if your here, your one of the guys.