I'm taking a look now
I'll provide feedback on the individual pieces and try to give some ideas.
First, about your belt issue, I'd say you should make different ones for the differing waists and group each type together to prevent confusion.
Now... feedback! Some of this is for older items since I didn't give it at the time. Mainly small tweaking issues.
Your black heels with the ankle band don't seem to have enough contrast. I can't figure out if its just my screen(which has been troublesome with determining shading) or not, but they don't have the same shiny-like quality of their red counterpart.
The curve of your boots(the one of the left side of the screen) seem to interfere with the legs. It just doesn't seem right visually and it looks like the boots should be a bit higher, with the curve at the inside of the knee.
I didn't notice this until using the gloves, but the hand on the hip is very... claw-like. It looks strange with the gloves, especially the shorter ones.
I LOVE the dresses with the ribbons! The red/brown combo is cute. I think the blue/white is nice too, though as a matter of taste I would've liked more of a medium blue. I really like your white/black off the shoulder dress. Its so classy and perfect.
Squees over the "Dollster" shirt! Way to represent. The red looks great on the grey shirt, almost like its shiny blood on it
I'm loving the ribbed turtleneck on the edging. You should do something similar with the v-neck, it would look great!
Stockings/nylons. I was making up a doll with that newer red jacket and it struck me how nice they would've looked with a pair of heels.
Sandels. It'd be a nice add for spring, especially since you have some nice spring clothes in there.
Long Dresses. Yes, I'm putting forth the challenge of a long dress. Maybe a mermaid style or something with draping. It'd be a good practice and I would personally love them. Then, you could add shrugs/shawls too for them.
Clutch purse. This fits into the long dresses xD I know I'm suggesting this purely because I love them, but they would look great with the long dresses!