Many way's like having it with you while walking and some kind of berries.
certain pokeblocks can make Pokemon happier if your talking about Pokemon emerald or Sapphire, but generally the more you raise your Pokemon the happier they become.
sooth bell
Not allowing it to faint in battle
I'm not entirely sure but I have heard they are in the Underground. Go there to make your Pokemon happier.
Give a soothe bell for your Pokemon to hold. Use that Pokemon in battle to beat others but don't let it faint. Do not use energy roots or powders. Also, a Pokemon that travels with you will be happier than one that doesn't. In Pokemon Sun and Moon, you can also give Pokemon beans and take care of them when they get harmed by the weather. This keeps them so happy that sometimes they will snap out of things just to make YOU happy, which is awesome.
if your Pokemon level ups, its happiness will increase automatically. but if you give your Pokemon a soothe bell, its happiness will increase faster, and it will evolve faster (by certain Pokemon). also return will do more damage
I personally think that Pokemon is fun because it is interactive and you get to.... kind of spend time with the Pokemon. You can level them up, make them happier, give them items or berries, and even make them evolve into a, sometimes, completely different form. Pokemon is one of my favorite games -Brady
Not really, it is just a sunset. It is beautiful, but it doesn't make a person happier.
No, but if you're nice to them they will become happier.
They don't have emotions, if you mean which one will make you happier, only you can answer.
Yes, he seems happier today than he was yesterday
it makes them happier and lets them grow levels faster. PS you can spread it by putting other Pokemon in your party.