I'll let someone else detail why having a comprehensive business plan isn't necessary, but a good primer for you is the Pitching Hacks book (PDF) by Venture Hacks. It's $9 but worth more than the sproutbean catfart health wrap you'll otherwise spend that on. Some of the things you raise here are brought up in their book -- which is actually more like a guidebook than a "book," per se.

http://venturehacks.com/pitching