Sansevieria likes to dry out completely between waterings. The most common mistake made with these plants is overwatering. Even if your plant is placed in ample bright indirect light, you won't need to water it more than once every 10 days (at most) during the growing season.
Sansevieria plants prefer a loose, well-drained potting mix. This plant will do well in sandier soils. Pick a potting media low in peat, which eventually packs and refuses to re-hydrate or drain properly.