My recommendation is this: Especially when starting out, stick to one state. There's enough to learn there, and certainly enough judgments already there, and more coming every day.
Then, after learning one state, you can generalize what you've learned to other states. The rules will vary a bit, but usually not all that much. Also, remember that there are certain limitations in some states. For example, no bank garnishments in Delaware, and no wage garnishment in TX (under most circumstances).
And, some states I strongly recommend against starting this business in. I've listed those elsewhere on this site. Or please feel free to give me a call to discuss. Thanks.