Rules of [Green] Thumb
Light
Choose plants that fit the lighting conditions in your space. South facing windows give bright, direct light. Direct light, especially in Tucson, can be too harsh for many houseplants. You can mitigate this by using sheer curtains to diffuse the light. East and west facing windows give moderate light — direct light in the mornings and afternoons, and moderate light for most of the day. North-facing windows give low to moderate indirect light.
Water
It’s better to underwater than to overwater! Many plants can bounce back from a spell of thirst, but root rot is a far more difficult problem to treat, and sometimes it’s simply not possible to do so. If the soil is dry 2-3 inches deep (use your finger), go ahead and water. If it’s still damp, wait. You’ll notice that watering schedules will change seasonally. You’ll need to water far less in the winter than in the summer.