How Do You Make Your Pokemon More Friendlier?

There are several ways to make a pokemon more friendly;
- Battle with it and don't let it faint. Equip a soothe bell to it if you have that item, it'll make your pokemon more friendly.
- Give it as many massages/haircuts as you can. Where you can do that depends on what game you have.
- There are some berries that increase friendliness, but they do lower stats.
- Give it medicine like carbos, zinc, etc, it'll also make your pokemon more friendly. These can also be used in combination with the berries to get the stat back up. However, the medicine are expensive and there's a limited use.
- Do NOT trade it. Once a pokemon is traded back and forth, it's friendliness will be gone and you'll have to start over again.

You can train them, but they get more friendlier with the soothe bell, I recommend putting a exp share on the pokemon and then just train them like that because your not making the faint in any way, or get hurt.

This is the way I do.
I put the pokemon I want to be friendlier a soothe bell. While I train it, it has the soothe bell at everytime.
Don't use the berries because they lower their stats. You can get the soothe bell in the pokemon mansion where it is the trophy garden, get it from one of the maids