Watch the Tweaking the 3rd online guitar lesson by TrueFire from Play Blues Guitar 6: Soloing Principles
Tweaking the 3rd - Concept 17 is a video guitar lesson presented by Jeff McErlain and is sourced from Blues Guitar Survival Guide - Lead.
One of the best tips I can pass along that will almost instantly make you sound better is learning how to tweak the third of the scale. In a blues we are very often playing over a dom7 chord which contains a natural 3rd. The minor pentatonic scale contains a flat 3rd. This is a potential problem as those two notes are a 1/2 step apart and can really be unpleasant. To remedy this we can bend the flat 3rd to either the natural 3rd or the ever cool quarter step bend. Getting control over this bend it essential to playing guitar, not just blues. Like everything, we need to consciously practice this. There are so many subtle ways to play it and they can all sound different. I find it endlessly fascinating.