Without defying my love for structured clothing, I must admit that I often slip into loose sweats or pants - they are as snug as a bug in a rug and take no sweat to style. Fitted/semi fitted top are most compatible with these pants. Loose on loose outfit is not flattering at all.
Showing off ankles with a loose pant is a big contrast which flaunts the legs. Complete the look with pointed heels. Or you can cover your heels with loose flowy pants to create illusion of long model legs.
My personal favorite is loose trouser with a fitted top and structured blazer. Wow! I just got another post idea ;)