I clip both my top and bottom threads about three inches long (I reach under the quilt to cut the bobbin thread). I bring the bobbin thread to the top by pulling up on the top thread and use an awl if I have to to grab the loop of the bobbin thread. I tie them off twice and then use a needle that the threads snap into rather than having to be threaded. Then I bury the knot about 1.5 inches away and cut the remaining thread. I know you can just back stitch and cut but I'm worried about the threads coming loose over time so I knot and bury the treads just in case. If my thread breaks while I'm sewing,or I run out of bobbin thread I pick out enough stitches so I can make the knots. I do this as I go so there is no chance of sewing over threads or getting threads tangled in the stitching on the backside.