Instructions
Place Azurill in your party and walk or run around the map. Pokemon gain one happiness for every 256 steps taken in the game.
Give Azurill lots of vitamins. Vitamins are potions that boost a Pokemon's status, including HP Up, PP Up, Calcium and Iron. Each dose of vitamins raises a Pokemon's happiness level by up to five points.
Take Azurill to the groomer or masseuse, depending on the version of your game. Pokemon can be groomed or massaged once a day, and each visit raises their happiness level by three points.
Avoid having Azurill faint in battle. Fainting will cause the Pokemon to lose one happiness point. Also avoid using Energy Powder, Heal Powder, Energy Root or Revival Herb. These medicines cause your Pokemon to lose up to 15 happiness points.
Take your Pokemon to the Happiness Rater. The Happiness Rater is found in every version of the game, though his location differs. The Happiness Rater gives you a general idea of your Pokemon's happiness level, with the highest statement being, "It is super friendly towards you! I'm a bit jealous!" Azurill turns into Marill when its happiness level reaches 220.