Bad Left hand Posture ?

[bcdon***]

any advice on good left hand posture would be greatly apreciated

I think it just boils down to what works for you. To avoid wrist pain make sure you warm up a bit (simple stretches, scale runs, &c) and take breaks every now and then to relax. Some of us are more prone to this sort of pain than others. I work on a computer all day and if I am not cognizant of my hands I get really annoying pain flare ups.

[groverj3]

Take any advice about technique with a grain of salt... people often say that their method is the "best" and all others are incorrect. If you know much about guitar you know that those people are full of themselves. Take one look at Marty Friedman and tell me that anyone ever told you to hold your pick like that .

However, I've been told repeatedly that the baseball bat/thumb over the neck method leads to tendonitis when you try to play fast, or stretch your fingers further. Playing slow may not cause the same problem. I've always tried to keep my thumb behind the neck, not always as far back as classical players, but almost never is it over the neck. This might just be due to most of the players I listen to doing it that way though.

I'd try keeping your thumb in the middle of back of the neck (that made sense, right?). If it doesn't work for you, then do whatever is the most comfortable for you. Keep in mind that trying to change your technique takes time, especially if you've been playing a long time. So if it doesn't seem comfortable right away that doesn't mean that its necessarily wrong.