You could get all your Clarissa Explains It All garb at Urban Outfitters . But then you'd have to shop there.
The Braided Crop Top
Fashion this out of an old t-shirt. Get the directions here.
Source: lefanciulle.blogspot.com
Reworked Shortalls
Get the instructions here.
Source: drifterandthegypsy.com
I mean, just look how adorable Claire Danes looks in them.
Cage Bralette
This looks like something Naomi Campbell would have worn underneath a blazer. Made from elastic and an old pair of stretchy spandex bike shorts. Get the directions here.
Source: elleandish.wordpress.com