For a pokemon that evolves by happiness you need 225 points. If you catch a pokemon by a friend ball it gains 200 points, if its another ball like a great ball you gain 70 points. Every 520 steps it gains 1 point. For every ststus UP item used on it, like carbos it gains 2 points. For every new level it gains either 3 points or 5 points. Every time Blue's sisiter grooms your pokemon it gains 3 points.

The underground hair cut brothers, the older brother.($500) 1,3,5 points depends on how happy the pokemon seems.

The younger brother.($300) 1,3,10 points depends on how happy it looks.

Happiness can go down to.

pokemon faints: -1 point
If Heal powder, Energy Powder, Energy Root is used: -5 points
If Revival Herb is used on the pokemon