There is a tutorial on how to do Dawn's hair style XD
Her main top is a black vest,
so maybe this pattern: http://www.simplicity.com/p-2095-mis...ned-vests.aspx
or hunt for a black vest that is long enough, and add to it.
the under top is just a white shirt by the looks of it
and the skit looks like its doubled. So you would have the main part of the skirt, and either pleat or ruffle the second layer at the bottom.
"SecretLifeofaBionerd" on Youtube did a tutorial on how to make the skirt I am talking about. you might just have the modifie it a bit to match Dawn.
The boots you could just look up random tutorials on boot covers or just buy pink boots, socks and modifie them to make it the way you need it to be.
The hat, http://clearkid.deviantart.com/art/F...orial-68772035
that tutorial is amazing and really helpful when it comes to making fleece hats =D
I hope I helped in some way ^^;