Watch the Add The Maj 3rd: Over A Blues online guitar lesson by Rob Garland from The Guitarist's Pentathlon

Next I'll add the major 3rd to the minor pentatonic scale in a blues context, utilizing it on the I chord because the tone can be found in that chord and therefore sounds very melodic. By acknowledging the major 3rd on the I chord and playing more traditional minor pentatonic on the IV chord you can take your blues playing to another level because you are addressing the changes.