I try to fret notes right against the fret. E.g. a G on the E string, would find my finger right next to the 3rd fret. This makes a slightly cleaner tone and will make it much easier should you decide to take up fretless.
I also try to use the tips of my fingers. Another thought is to try to time the press of your left hand with the pluck of your right. I don't want to waste energy holding down a note that is not going to be sounded for another 1/2 second
I'm all about economy of motion when I play. I've been working hard on it for over 4 years and it's starting to pay off. But, I still have a long way to go.
I try to keep my left thumb on the centerline of the back of the neck or below (towards the treble side). This makes it easier to get my fingertips on the strings and my fingers (left) coming at the board from an angle close to perpendicular. I've actaully seen pros playing 5,6,7 strings who don't even move their thumbs to the back of the neck - they just rest it on the BOTTOM edge of the fingerboard.
In short, I try to never let my thumb go over the top of the neck under any circumstances.
One other rule I try to live by includes always trying to alternate my right hand fingers in practice. When performing, I play what I play, but I think about what I play when I practice (easy for me to say).
As far as one finger per fret goes, I'm able to do that but I don't hover the fingers over the frets - especially for the wider spacings down at the low end of the board. I move my hand in kind of a rolling motion (hard to describe) to make longer jumps. In other words, if you try to hold all four left hand fingers at the spacing requiured when playing in first postition, you will hurt yourself quickly unless you have giant hands. I could never do this, so I worked on being very smooth in this rocking motion I've described. It's mostly in your wrist.
Remember tension is the enemy of groove. If you are contorting your hands in any way, you should re-think your approach to playing that passage. Use your head as well as your fingers and you will make fast progress.
Good luck. Rock on.
