Amazon business growing, looking for advice moving forward!

Hello Sellers,

I am relatively new to FBA (6 months) and am looking for some advice on the next steps in my journey. My sales are ramping up and I have already trademarked, Brand registered, gotten quality pictures /videos, and am running campaign’s. I do not want to be caught off guard with book keeping or looking back on a detail I missed as my brand grows. I wanted to know what should I be keeping an eye on and/or what software others use for book keeping? I want to have my ducks in a row as tax season is quickly approaching, any advice on this would be greatly appreciated! ( I also would like to know others experience with paying taxes on items sold in other states) Thanks!