Its a long road with many pitfalls mate , slow down a bit and think before you leap.
The NASC cost money and there is prerequisite to joining , look on their web site all the info should be there. Have you been turned done for a job because you are not a member ?
what sort of work are you after ? The most important thing in any business is " Cash flow"
so how often will your customers pay you ? bigger firms are paying 30,60,90 days and most are always using excuses to not pay you on time. Some of my best customers are small painters and builders because they will pay you quick whilst there work isnt always big money it keeps your cash flow going. Roofers work is also good as they only usually want a top lift of boards so less boards.
my advice to you would be take pride in your work as that will be your best advertisement and try not to hire gear unless you really have to,
and remember there is a real danger of growing to big to fast