Instructions
Equip Eevee with the Soothe Bell to increase its happiness growth-rate. Feed Eevee vitamins like Iron, Calcium and Zinc.
Restore Eevee's HP with Fresh Water, Soda Pop, and Lemonade instead of standard potions like Super Potion or bitter herbs like Energy Root.
Give Eevee a daily massage in Veilstone City. Switch out or heal Eevee to protect it from being knocked out in battle.
Repeat Steps 1-3 until two big hearts appear next to Eevee's sprite in the Poketch happiness checker. Raise Eevee one level during the evening or night hours and it will evolve into its fifth evolution, Umbreon.