This is Video 6 in the series "Personalizing" your play, or "How to create your own style." If you have not yet watched the introduction to this series, please do so, as otherwise this will make no sense!
In the following clip. we are adding a dropped thumb in anticipation of the melody notes. This is quite a bit trickier than the preceding bits, so unless you are completely comfortable with drop thumb playing, don't worry about this.
For best results, you should experiment with using a dropped thumb to play "drone" notes other than the 5th string: the 4th and 3rd can be quite useful. You'll notice in the video that I combine this a lot with hammers and pulls.
Watch this video clip in which we add drop thumb. You can download a .wmv version from this site by right-clicking on this link: improv_drop.wmv
Here's tab showing sorta what happens around 1:44. Please note this is not a transcription, but it is pretty much what I was doing in the video. You can download this Tabledit (.tef) file by right-clicking this link: rhythmic_thumb.gif.