Welcome to the FISD, Noah, and great to hear that you have ordered your armor! As has been mentioned, research is the key to a successful build. Another bit of advice is to take... your... time. Trying to rush through a build can (and usually does) lead to "oops" moments. When in doubt, ask. We are here to help every step of the way!
Another thing I suggest is to get all of your build supplies in order before starting. Having things on-hand and organized will make life easier. Trust me.
As Andrew mentioned, there are 2 optional accuracy levels after Basic 501st approval which are honestly not that difficult if you want to go the extra mile. It's much easier to tackle these during your build rather than after, and the extra work will definitely pay off with a much better looking set of armor.
If you have already joined the Outer Rim Garrison you should ask about "Armor parties". There may also be some local TKs that are willing to help in person, but know that we are here for any and all advice you need.
Have FUN with your build, and I look forward to seeing you around the forums!