Sadly, I begin by putting the book next to my bed and letting it gather a bit of dust first. Once it has acquired the necessary amount to beat out its dust-burdened contenders, I wipe it down and flip to the last few pages.
Yes, I know what you are thinking. Why would I start with the back?
Too often, I'm disappointed with endings. I learn more from the last few pages of a book than the first few. If I was an agent, I would ask for the last two chapters of a book.
Okay, that's not entirely true. I do think a beginning can make or break a book, but that's before I'm invested. A bad ending is after pages and pages of investment.
And, yes, I have ruined a few books this way, but I still felt compelled to read and see how the story ended up there.
Do you have any ritual before you start reading?