He doesn't evolve at a certain level. He evolves by getting his happiness to 220. You can increase happiness by:
Walking 256 steps
Massage (Veilstone City)
Massage (Ribbon Syndicate)
Using vitamins
Level up
Using EV Berries^
Conversely, you can lower happiness by:
Fainting
Using EnergyPowder
Using Heal Powder
Using Energy Root
Using Revival Herb
Haircut brothers (HeartGold, SoulSilver)
Daisy grooming (HeartGold, SoulSilver)
Also remember that you will reset his happiness if you trade him. Pokemon bred from an egg start off with a happiness of 120, and if you trade him, it will drop to 70 for most pokemon.