Are you going for venture capital or an angel investment? The level of documentation and requirements will be similar, but at the angel level the chips are stacked more in your favor as far as getting meetings and investment. Angels are not going to expect a minimally viable product or traction as much as VCs will.
A few sites to check out:
http://www.venturehacks.com
http://www.markpeterdavis.com/
Every VC is going to be different in what they want and don't want to hear/see. Remember going in that the odds are against you. To increase those odds you can show traction in the market, and at minimum a working product (even if it is not the final product).
Angels and investors are going to want to know about your background (i.e. school, previous work, and any startups you have done in the past).
Essentially it is a dog and pony show where you have to prove to them that you can execute on a product and make a return on their money. While a return is not always going to happen, the more comfortable they are with you, your product, and the chances of making a return on their investment the better off you are.
Get a lawyer, one who is experienced in raising outside investment. There are laws that you must follow when seeking outside investment and having someone familiar with the process is essential. Be ready to spend some money on the lawyer (most lawyers will work with the intent to take their fees off the top of the funding when finalized).
The final thing is it takes time. Keep working on your product and unless you absolutely need money focus on your product more than raising the funds. It could be as short as a couple months or as long as a year or so before you see any funding. Work your connections. The best way into a VC or angel is through connections. Cold calling/emailing is a one and a million chance of getting someone to meet with you.