Well, what females do you have or are looking to have? I got a few pics I could show you.
CROWNTAIL: obvious. Hers however are rather messy, some will have a cleaner line, and better rays,
PLAKAT (avatar) the ANAL fin is what you look at. That fin, compared to a veiltail should NOT swoop under the caudal (tail). Plus they are usually thicker bodied.
VEILTAIL, as mentioned above they should have that swoopy anal fin. (pic curteousy of google) they may also have longer fins, and some can be mistaken for juvenile males.
DOUBLETAIL: do not have a picture, but these you should be able to identify.
HOWEVER... there is what I have, and I have mistaken as a veiltail. doubletail geno. There is no split, however the dorsal, caudal and anal are all very wide compared to a veiltail (picture of my Janey shown) excuse the rough shape of her caudal... I bred her before this picture was taken.
Combtail, picture curteousy of google. Won't have the full on spikes of the crown. Not much I know about these fellas, someone may have to fill in
Hopefully I kinda sorta half helped :)
***** edit: doubletail picture, my own, of a 3 week old fry. split in the tail. females will have this, and obviously not as long of fins as a male would.