It's been some time since I've posted anything about my one of my minor passions, the love of a good first sentence. I've said before that the search for a good closing sentence may blind you to the fact that you've already written it.
Here, via Bryan Garner (not to be confused with Brian Gardner), is advice that feels somewhat familiar:
The best practical advice that can be given [on how to frame the opening sentences] is don't start. That is, don't start anywhere in particular. Begin at the end, begin in the middle, but begin. If you like you can fool yourself by pretending that the start you make isn't really the beginning and that you are going to write it all over again. Pretend that what you write is just a note, a fragment, a nothing. Only get started.
Stephen Leacock, How to Write 27 (1943).