This method is more effective in the beginning of game, especially when you have to get your two first badges. First, catch a Kricketot and train it by using Bide until it evolves into a Kricketune. It will then learn new moves. Use the same trick with Machop so it also learn Bide. These Pokemons are helpful when they are stronger, especially when facing the second Gym leader and chose Piplup in the beginning).