The first thing that catches my eye is the color/design. If I like the feel, it's as good as sold. LOL
I like many different brands Kaufman, Hoffman, Clothworks, P&B Textiles, Benartex, etc. Sometimes I buy new releases, but more often I find I am waiting and getting the same prints later on at better prices online.
I shop both in the LQS and online. Nothing beats seeing them in person, and I try to help keep the LQS in business. But once I find brands I like, I have no problem ordering them online as long as the ordering page is secure.
I have tried many online sites and have been happy with most of them. My most frequent purchases come from:
Over the Rainbow
Thousands of Bolts
SeaWatch Fabrics
Desperate Quilters
Webfabrics.net
Some I've tried once and would definitely shop again:
Quilt Fabric Closeouts (pics do not do the fabric justice)
Fabric Shack
Log Cabin Quilting
Green Fairy Quilts
Toadusew
The Quilted Castle