Right now the more mainstream fashions for girls in Japan are...
Long flowing skirts (some can also be pulled higher up and worn as dresses) with a very small denim (or other colour) waistcoat/jacket over it
An oversized t-shirt with a bold logo/big Engrish words and colours, with a short frilly skirt under it (very cute!)
Checkered shirt-type dresses (hard to explain but I bought one yesterday so I'll try to post a pic later) worn with these strappy brown sandals which sometimes have straps going quite far up the leg
Cute flowing blouses (some with flower patterns) worn with mini denim shorts
And more! And of course the high heels that about 98% of girls seem to wear...
I'm seeing these fashions all over Tokyo right now (especially the 3rd one) and I saw them in a recent non-no issue. Such cute summer fashion
I'll try and post some pics later!