It seems to me that while there are many YLF-approved fashion items, there are a few that are extra-specially encouraged, and a few that are frowned upon. Sometimes I don't feel like I'm fully participating because I just find it so darned hard to pull off the "encouraged" things (and I admit to owning the "frowned upon" things and I actually think they look pretty cute)! And they are:

Encouraged:
-belts (only possible for me under very limited and specific circumstances)
-tucked-in tops (my personal style armageddon)
-ballet flats (these manage to make every skirt I own look frumpy)
-hosiery (actually, I've come to like some types of hose)

Not Approved:
-flip flops (why am I not allowed to wear these in the summer? They're so cute)
-Uggs (I do see why these are useless out-of-doors, but I think they look good with skinny jeans tucked in)
-short sleeve tee shirts (but, but, these look good on me! Fitted ones, that is)