Mix potting soil with washed sand and gravel in equal parts.
Plant the cactus in the soil mixture.
Place a large rock near the cactus to help it maintain heat during cold winter nights and cool off during the summer heat, thus requiring less water.
Water your cactus once a month. Adjust watering depending on the climate and where you have the plant--potted plants require more water than ground cacti.
Keep indoor cacti near a window to get ample light.