Another thing that will cause thread to tangle is working with too long a length.
While it's nice to not have to thread needles as often I have had to make myself work with a shorter length. Works much better, and I never knot my thread when hand piecing I just do about 3 stitches in a "backstitch" to secure a seam. It eliminates the problem of hitting a knot if you're hand quilting. I do use a knot when hand quilting though.