Where does it tell you how to get customers? I always saw that as the biggest obstacle.
You may be a programmer now, but once you start your own business, you are now a businessperson first, and a programmer second. This is a critical change of state that you must make. Like almost everything else, you shouldn't count on anyone telling you anything. You are no longer someone's employee. You must initiate the finding of all "how to's".
You are correct in believing this is the biggest obstacle. Without customers, you are dead. With them, you can solve almost any problem you have.
As far as getting them, you can (and should) try just about anything. Some of my experiences:
All my computer work, including job-type jobs I've held, have all come through networking. But that's really just a truism I guess, in that all work will/must come from networking. Which I take as your point...
What's interesting to me is the way one's personal network, seems to grow; like the facts of networking are stranger than fiction in an organic "Connections (BBC)" sorta way.
(Been watching old connections episodes on my G1 off youtube, while the inet is out at my house. Great show.)
http://jacquesmattheij.com/be-consultant/finding-keeping-cus...
The amount is a fixed percentage of the invoices during the first year, 12% is my current percentage.
I spot someone that has a very fat rolodex and I tell them I'm willing to pay a referral fee.
It's quite effective.