I'm a fan of the "zig-zag" method. When puppy shoots ahead of you (even before she has the opportunity to pull), you change direction abruptly. No warning, no cue. Just change direction. Be careful not to jerk excessively (your puppy is still a growing, fragile being), but surprising change in direction will, in theory, encourage her to keep an eye on you for direction and leadership. Also, it will communicate to her (very similar to the "be a tree" method mentioned by AKBull) that in order to move forward, especially toward fun or interesting things, she does so by walking beside or behind you... not by racing ahead or pulling.