I learnt everything I’ve ever needed to know about music theory from 2 places…
1:) Playing a lot of songs and noticing patterns.
2:) This book by Hal Leonard
3:) Finally reading and studying the book above by sitting a music exam. RGT Grade 5 Theory Exam
How to learn all the notes on the guitar neck – Part 1
How to learn all the notes on the guitar neck – Part 2
Beginners 12 Bar Blues Guitar Lesson With 15 Essential Chords
P.S. There’s a guitar music theory webinar series at The Premium Student Area