If you are leaving your home for a while, or you simply have potted plants that require high moisture, you'll need to find a way to keep the plant's soil evenly moist as much as possible. Several types of products help retain moisture in soil. In addition, if you place pots wisely and keep the home environment sufficiently humid (if the potted plant is indoors) you'll extend the amount of time that must pass between watering.
Add water-retaining granules, discs or spikes to the plant's potting soil. These products hold onto water, then release it as the soil dries. When you mix them with the potting soil, they will help keep the soil more consistently moist. Most garden stores sell these water-retaining soil amendments.
Place the plant pot (if the pot contains drainage holes at the bottom) on a saucer or plate covered with water. This allows plant roots access to moisture from the bottom of the pot.
Place sphagnum moss or wood chips on top of the soil. Doing this helps slows water evaporation from potting soil.
Move the plant away from direct sunlight and other heat sources (such as indoor furnaces or stoves). The sun's burning rays will dry out plants quickly, as will being too close to heat sources.