Research the Nationals you choose. Find companies and apply... Look at their price list and understand it. Some pay what they say, some pay the price minus a discount (which varies)
Make sure you know and understand your allowables and know what you can and cannot do at a property. Last thing you want to do is work for free. However, you also want to take advantages of making as much as you can and taking care of all you can during a trip to the property.
Read your work orders well.
Some companies are great and you can call with questions. Others don't allow calls at all and tell you "it's all in your work order"
When in doubt, we bid. Every bank is different, so bid and notate anything you think may be an issue.