OK... here is what I think sets you up for best chances... but keep in mind, I am early in the game here so not proven this out....i could be way wrong
1) Plan to write a series for your debut.. talking at least 5 books.
2) Give book 1 away free, charge low price for rest of series like 2.99 or something.
3) Submit your book(s) to EVERY review site, blog, etc that takes books of your kind. (I still need to do this actually)
4) Get as many friends and family to buy your free book on Amazon as you can, that way it shows up in the "ppl who bought this also bought" lists on Amazon.
5) Make sure each book in the series leaves them wanting the next book.
6) Get yourself a blog site and blog about your book, post links to your blog every where you can
7) Lots of prayer.
I think you need to at least that much to put your self in the position of having a chance. This all assume your writing is worth reading btw...