SPORTPLANE CONSTRUCTION TECHNIQUES BY TONY BINGELIS - this is a great reference book for tons of stuff.
AC 43.13-1B - Acceptable Methods, Techniques, and Practices ... - the bible for repairs, but also gives great info for guidance on acceptable practices.
There are lots of books available that you can see with a quick online search.
Matronics forum for the specific aircraft you are building is full of useful, interesting and sometimes not so useful info. Great way to lose several hours!
Lastly, there are usually lots of other builders of your aircraft that have an online presence - get in with them and start asking questions!
Mark (sorry about the font.....)