To thrive in your home, orchids require the same kind of attention you give your other plants, but watering is most important. With some exceptions, keep the potting medium moist but don't let the plants sit in water. This generally entails watering once a week. When growing cattleyas, allow the potting medium (porous ground bark) to dry out between waterings.
Occasionally mist the air around the plants to increase humidity. Or, set pots in a pebble-lined tray filled with water to just below the bottom of the pots. When the plants are in active growth (producing roots, stems, and flowers), feed them weekly with a water-soluble orchid fertilizer. When the plants settle into a resting period and don't grow, fertilize every other week. Repot as needed according to Potting an Orchid.A Bit of Natural History
In their native tropical habitats, orchids often grow on tree trunks and limbs. As epiphytes, these plants take moisture and nutrients from the air around them, not from soil. Indoors, they grow best in a loose, porous medium, such as pine bark, or a mix formulated for orchids. Such mixes may include bark, sphagnum moss, and charcoal.