If you want to get really fancy try this. My buddy doesn't like knots so he has another plan. He shaves down a piece of heavy leader to a point. Then with a dental tool he pushes the core of the fly line back up inside itself to make space for the leader. A dab of crazy glue and then he slides the leader up inside the fly line. Let it set, test it and you are ready to go. No knot, no bump. When fishing over 20 foot leaders you can go a long way until you reach a knot this way.