Start charging yourself by the hour for the re-designs. After a while you'll stop making adjustments to make it more cost-effective. lol
Seriously though.. sometimes I'll bookmark pages that I like, or that inspire me, and try to either mimic them or use bits and pieces from various sites that I like and put them together. I'll also spend quite some time in photoshop to "brainstorm" a bunch of ideas before actually coding any of the pages. It's easier to throw out a design that you've spent 10 minutes on in photoshop than one you've spent hours on coding in HTML and CSS (not to mention the headache of figuring out simple bugs, only to realize you don't like the design in the first place).