One of the best things about the Peace Lily is that it sags slightly when it needs to be watered. In general you need to water it once a week and ensure the soil is moist. Throughout the summer season, spritz the leave with distilled water.
When it comes to fertilizing a peace lily, any good quality, water-soluble houseplant fertilizer is fine. Look for a product with a balanced ratio, such as 20-20-20, diluted to one-half or one-quarter strength. Be sure to water after feeding your peace lily to distribute the fertilizer evenly around the roots.
Peace Lily's thrive in partial shade in even flourescent light can work well for this plant. It can often thrive in a room with no windows with just enough flourescent light. Yellowing leaves indicate that the light might be too strong.
Peace Lily's thrive in temperature from 18 degrees celcius to 29 degrees and humid clients. Keep them away from direct AC drafts and it's best to keep them indoors throughout most of the year.
The plant will wilt because even though you may water generously, liquid simply runs through the drainage hole. If your peace lily is severely rootbound, it's best to repot as soon as possible. If your plant can wait a little longer, spring is the ideal time for repotting a peace lily.