I have come across this article about making money in the reefer business. According to it, there are 7 steps in order to start the business.

1. Use clean and good equipment (no junk trailers).
2. Know your seasons (produce).
3. Know truck densities. How many trucks you are competing against in a particular area.
4. Know the rates. Usually later in the week means more money. Running a team seems to be the most sought after, and make sure they pay for it.
5. Choose brokers wisely. This is the hard part because you have to find brokers that won't screw you. Ask questions and research them so you can get good information about them.
6. Be patient in selecting a load. Calculate it, not just because the load pays well; going out or back, add the total miles and tolls and your fuel minus out your gross = net.
7. Remember cheap freight will hurt you. Never start a relationship hauling cheap freight. You will get tagged and will regret it.

Hope this helps. For those who are starting reefer business or those who already took off, please post your tips here.