Short and Concise

So I've always wanted to write a book. I wrote some and then stopped because a couple of publishers sent me a 'not interested email reply.'
But this time I'm going to finish my story and not stop at least until maybe 500 publishers say "no". I mean that's a lot of "No's". I have to stop at that point.
Up till now I have just managed to write down a rough plot summary and a vague outline sketched out.
Fingers crossed, will follow through till the end on this endeavour.