I'm going to shill for 6-string basssist and teacher Todd Johnson and recommend you get his "Technique Builders" DVD (either alone or with the book).
Easily THE single best resource for... building your technique (go figure). Not cheap, but well worth every single penny.
Todd's on-camera manner is very supportive and easy-going, kind of like having a buddy help you out - and he has his own forum here on TB if you have any questions.
He is strictly a finger-style player guy (i.e. no slapping), so keep that in mind... and the DVD is applicable to 4-, 5-, and 6-string instruments.
This one DVD made a very real difference in my own playing, & I keep referring back to it, fine-tuning the techniques Todd demonstrates.
JMHO
p.s. - as a "bonus", you get Todd explaining/demonstrating the "floating thumb" thing, which has *finally* become my "normal" mode of playing: now when I pick up my bass, my right hand automatically goes into floating thumb position/mode as natural as you please.
