Layer the bottom of a planter with broken crocks or some gravel. Stand the peace lily with nursery pot in the planter.  
Alternatively, transplant it into a decorative plant pot. Cover the bottom of the pot with a layer of broken crocks, add fresh potting compost and place the root ball at the correct depth. Fill with more compost and press firmly down. Water generously immediately after planting.
You could also just stand the plant in its nursery pot on a saucer and water it there - do not allow it to stand in water longer than a day.
The plant should be stood in a sunny position in the living room but out of the direct sunlight.
 

Water your peace lily regularly (twice a week in the summer, once a week in the winter) keeping the roots relatively moist. During the growing period add feed to the watering can (once a month using fertiliser for flowering houseplants). The peace lily prefers a humid atmosphere, especially in the winter - beware of central heating! Stand the plant somewhere cool (around 15 degrees centigrade) in the winter. Leaves that turn brown and faded flower stems can be snipped off.

Dormant period

If your Spathiphyllum wallisii appears to have stopped flowering, reduce watering and stand it in a cooler place (at least 15 degrees centigrade). After a few weeks it can be returned back to its usual place in the warmth. This way the peace lily can flower throughout the year.
 

Spathiphyllum wallisii is a member of the Araceae family. The white spoon shaped ‘flowers’ of
Spathiphyllum wallisii are really bracts known as a spathe. When the pale green spathe opens it turns white. This is when the true flowers can be seen on the creamy coloured spike which is called the spadix. Even when the plant is not in bloom the fresh green pointed leaves make a really attractive foliage plant. The plant will flower for 4 to 10 weeks followed by a short dormant period necessary for developing new buds.