I developed a simple system I call the "Baroque" method to simplify learning how to improvise on the guitar and other instruments. It involves playing continuously using the primary key of the melody. It can be slow to start, but it quickly adds speed and versatility to your playing.

The CAGED system is the best description of guitar chord fundamentals. If you know the note positions (root, fifth, etc.) of the CAGED shapes you can quickly and easily expand your knowledge of the guitar fretboard.

Musical keys and modes are closely related. In my opinion, an understanding of both leads to the conclusion that modes are unnecessary. Knowing keys suffices for all situations, since every mode from any starting point is just another key.

Diminished and augmented chords are among the most interesting in all of music. They are easy to use, but require a bit of understanding of the 12-tone scale. This document explains those issues and gives some "cheat sheet" hits for easy remembering.