When to use the major scale?

Here are 2 simple solutions to: when to use the major scale?  Although there are many many many more uses and applications, this is a good starting point to understanding the application of this concept.

Example 1:  Use the major scale in order to come up with a lead guitar phrase or simple improvisation whenever you see a major chord.  For example, if you see an A-major chord you may play off of the A major scale.

Example 2:  This is a bit more out there and creative but here it is...USE the Major scale when you see a minor chord but use it a whole step down.  Example:  if you see an A-minor chord, go a whole step down to G, and use the G major scale in order to improvise some lead over an A-minor chord.

Keep playing!