Pretty much the same as ASparrow - I tend to use reviews and the dust jacket blurb to get an idea of whether the plot appeals to me. If I'm interested, I usually read the first page or so and a couple of random samples from the middle of the book to see whether I like the author's style.
Then I take a photo of the front and back cover with my mobile phone and store them in my "to buy" list until I buy the e-book
