The thing is, when a reader picks up your book, your first page carries the very heavy responsibility of grabbing their interest and not letting go for anything - every line must make the reader want to read the next, or it doesn't belong there. When I'm sampling a book, I generally read until I don't want to any more. If I've made it to the end of the first page and I'm still interested, I'll buy the book, or at least add it to my reading list. If I lose interest somewhere before that, I put the book back and move on. And we all know it, I'm not the only one who samples books in a similar manner.
Your first page should:
- Hook the reader.
- Introduce your protagonist.
- Make your readers care.
- Hint at conflict.