Hello Batistainc!
First, thank you for serving our country!
Second, a piece of constructive crtizism (nothing personal). If you can estimate your pretax earnings, but not sure where to get a business license...you need to take a deep breath and start at step 1 again. Try the Small Business Administration
here.
I talk to many people who get ahead of themselves with projected earnings, and then become frustrated when they see that their perception isn't reality.
Third, to answer one of your questions. Joining the local chamber is always a good idea. Just as GuyBBY said, there are many advantages. But don't stop there. Look for other networking groups. BNI is a large one, but there are many locally too.
Comming from the ad business myself, I can tell you that it's all about who you know...and you better know a lot of people! Start rubbing elbows now!