The first step is to consider the left hand thumb positioning on the back of the neck. More often than not, the ideal position for the thumb is opposite somewhere between the first and second fingers of the left hand. This does provide a nice solid base to work from when applying legato technique. More recently I have also experimented with raising the thumb position so that the inner side of the index finger touches the base of the neck.
This positioning gives me a little more strength and security when I am playing in the lower positions of the fretboard. It is not something I do all the time however but really as and when I feel the need to.
Feel free to experiment with these positionings to try and find the best position for you.