On first lines and writer's block

OK, so now comes the hard part. The first line.

I've jotted down a synopsis, built a chapter-by-chapter outline, received hugely helpful feedback on both from a very wise reader and now I'm ready to start writing.

But that means I have to surmount what is often the most challenging barrier for my writing projects: composing the first line.

I put a lot of pressure on that first line. I have convinced myself that a great first line is the key to selling a book to an agent, convincing a publisher to take you on, and eventually attracting readers in a bookstore.

I place so much importance on that first line that I often create an artificial case of writer's block for myself, even if I have the rest of the book completely and convincingly laid out in my head. I write and rewrite, devise and revise that line over and over again in my mind and can't force myself to move on to the rest of the story without getting that first line absolutely perfect.

So, right now, I'm playing with something like the following: "The first bolt of lightning struck about five miles away." or "Lightning struck. The building shook." or "..."

And now, when I type them out, I think: "No, those suck..." And all my confidence drains away.

Writing colleagues have advised me simply to hammer down a first line, the best I can come up with under the circumstances, and then keep on writing. By the time I get a substantial portion of the story written, I'll have a better idea of how to craft the first line.

At least that's the theory.

And then I wonder whether or not my problems with creating the first line of my book are not simply a psychological construct to permit me to delay actually engaging in the long-term writing process.

Ahhh, first lines....