By definition Shibuhara isn't strictly a Gal style, since its very name means it's a mix of Shibuya (Gal, ) and Harajuku ( Kajikawaii, fairy-kei, etc) styles. So I think of it as Gal diluted with cute.
Egg often has some cute Shibuhara exposure but the bible has to be Popsister. Here are a few images I found in Popsister 2010 issues. High quality scans were found on VVshu.com. Click for full size:
The staples of this style are cartoon printed (Mickey and Snoopy) and big slogan tees, colourful plastic-frame glasses, distressed denim, knee socks, black tights with colourful shoes, uggs,hi-tops, cute scrunchies, oversize hoodies, baseball caps and geeky bags. lots of cute pastel colours and prints. Hair and make up needs to be big and beautiful to avoid looking too casual.
Key Gal brands are Candy Stripper, Wakatsuki Chinatsu, Sby, Tralala and JSG. some non-Gal brands which fit this style are Pink Latte, Milkfed and Lowry's Farm.
My Shibuhara wishlist! Click to enlarge:
Here's a recent outfit of mine. Mark drew a Clefairy on the hoodie for me and the 'uggs' are synthetic.
Mark's doing his Amekaji look :)
And on a very cold day! Knit dress is Primark and boots are from a certain cheap Chinese webshop.
I'm looking forward to exploring this style more ^^