What IGBT said. Get whatever else you need so that you can work as your own boss, once you can.
Also, I worked construction before (mostly non-skilled grunt work) and one thing that is key is your name amongst other people. People in other crews eventually get to know you or see your work (or have to repair it) and on and on. This is especially true in cities of 100,000 or less. I found that word travels fast among labourers. Before I met someone there was a chance I had seen or could identify some of their work.
I'd even advocate you study communications (read How to Win Friends and Influence People) because your rep can go a long way for you and depending on whether people trust you and your work can land you more jobs through word of mouth like nothing you've ever seen. The labourers that people trust are more inclined to get repeat calls and, thus, more money. People don't like the guy who constantly takes breaks or who does shoddy work. If you do solid work and come across as a cool, nice dude, you will have no problem. If you can come across as -very- honest, knowledgable and friendly then you will be laughing to the bank.
(I don't know much about it, and even less about the trade, but this is just what I've seen and noticed over a couple of summers.)