Water the plant enough to keep the soil damp throughout the pot. How often the plant needs to be watered is dependent on how fast the soil is drying. Also, spray the leaves with water two or three times a week. This can provide extra moisture for the leaves and prevent them from turning brown.
Dampen a clean cloth and wipe it over the surface of the leaves to remove any dirt that may be interfering with the plant's ability to breathe.
Remove any brown spots on the leaves with a pair of scissors, cutting along the edge between the healthy green part of the leaf and the brown part of the leaf.