Hapiness for your pokemon tips.
1.If you want pokemon to be very happy, catch them in Luxary Balls.
2.Go to the SpaRibbon Club in the Resort Area and get their special treatment. Be sure the pokemon you want to be happier is in the first slot of your party.
3.Walk around and battle trainers! This is one of the unnoticed ways people don't see most of the time.
I hope this helps! :)