There are only two ways to increase a Pokemon's happiness. One way to increase a Pokemon's happiness, is to consitantly use it in battle. (Or in other words: Use it to fight alot). Another way to increase their happiness, is to feed them many, many poffins. A tip on the poffin one. If you look at your Pokemon's summary, you can find out what kind of poffins they like. If you feed them the kind of poffins they like, you have a better chance of them getting happier, faster.
Hope this helped!
Poke Chix
deleted by *jamopop*
How I increase happiness of Pokemon is talking to the lady that lives in Veilstone City who gives massages to Pokemon. I also give them status increasing medicine like protein. If you can give the Pokemon a soothe bell to hold it will also increase faster. This technique also works for increasing friendship; when I wanted to evolve a Golbat into a Crobat I used this method and also had caught it in a Luxury ball and it evolved after one level! You also need to keep the Pokemon in your party at all times and make sure it never faints; if you want the Pokemon to get exp just put it first in your party then switch it out right away in battle for a stronger Pokemon. That strategy also is recommended in the players guide for raising weak Pokemon.
from Satores
Pearl and Platinum
It has to have happiness. :)
get massages from the lady in cainwood city
Happiness is gained by taking care of your pokemon giving it items, training it and many more things. Once it's happiness reaches the max happiness have it level up to evolve the pokemon.
cleffa evolves into clefairy when its happiness is full, you can increase this by feeding it berries, giving it to the massage girl in veilstone city (Pokemon diamond, pearl, platinum), leveling it or giving it vitaminds. you can check its happiness in the Pokemon fan club in hearthome city (Pokemon dpp)
level up with base happiness at 220
It shows how much the Pokemon is happy with you. In some Pokemon you can evolve it if it has high happiness.
Pearl and Platinum
With the happiness checker you get in the Pokemon center in etera city.
If you have the happiness App. for your pokewatch thing... you can see how much your Pokemon loves you (how happy they are).
Maxed out happiness
It has to have happiness. :)
happiness and daylight
You have to let evolve from a Golbat by Level Up with Happiness Value at 220
Chingling must be leveled up at night with high happiness to become Chimecho.
Give it happiness
With the happiness checker you get in the Pokemon center in etera city.