FCC certification process for Part 15
Go read Part 15 to learn more.  Here is a video that will give you a very small taste of what is tested and how you can do some rudimentary testing yourself (maybe) link

It seems the most you can probably, really do is stick with sound design principles when designing your circuit and PCB and then work with a testing house to fix anything that went wrong.  Here are some google searches that can get you started link1 &amp; link2