How long should a beginning be? I often hear that question. My answer is: As short as possible. Some experts say not more than 100 words (about half a manuscript page). Instead of focusing on length, concentrate on it being easy to read and quick to absorb.
Give us enough words to pull us into the writing. Hold back nonessential information.
When I browse a book or a magazine I'll give the writer the benefit of one paragraph. If I'm not at least mildly interested, I stop. I always have a stack of reading material at my desk—more than I'll ever read—and so do many writers. I want my reading to be pleasurable and I don't want to work at reading.
For instance, two days ago I started to read a blog entry where the writer tells about an emotional experience while watching a film in a theater. Before she grabs us with the experience, in the first paragraph she writes about the price of the ticket and that she doesn't usually attend action movies.
I shook my head. Those two things may be important to her (spending money and justifying attending a film) but not to readers. I lost interest.
Beginnings contain only essential information to draw readers to the material.