I'm looking for all the ways to increase Friendship in Pokemon X and Y. Note that Friendship is different from Pokemon Amie Affection; they both do different things.
- Walking 128 steps
- Getting a massage (Cyllage City)
- Using vitamins
- Levelling up
- Using EV berries
- Soothe Bell (Shalour City)
- Using bitter medicine
Trading resets a Pokémon to its base happiness
Here is the happiness page from Bulbapedia. It has not yet been updated for XY, but the boosts from Gen V have not altered.
You can usually get a Pokémon to have it's friendship raised in many ways really. Like, if you give your Pokémon vitamins like protein, carbos, etc.. You can also raise it's friendship by letting it hold a soothe bell, walking around with it or just plain battling with it! Then if you level it up it might evolve! But beware! PokemonAmie does not raise your friendship, but it does raise chances of critical hits, evasion, and status moves such as endure. And stay away from letting it faint and feeding it herbs, hope I helped!
Friendship is increased like it has been in previous generations: winning battles with your Pokemon, using items such as Potions on it, and just moving around with it in your party. Note you can lower happiness if the Pokemon faints or you use herbal medicines on it. Pokemon-Amie is rumored to increase happiness in small amounts, but this is not confirmed.