Find a location. Decide on a spot to record. If you can't go to a professional studio, try to pick a quiet room away from distracting external sounds like sirens, opening and closing doors, and people talking on the phone. Read your script aloud, and pay attention to the room's acoustics. Does your voice echo or sound muffled? If so, consider recording in a different space or adding furniture to fill in the room.
Tripods range tremendously in price, and the quality of your tripod should depend on the level of camera and lens you have. If you're shooting with your phone, you can get by with a table mount like the Arkon Tripod Mount or a full-size tripod like the Acuvar 50” Aluminum Tripod. For a DSLR, Manfrotto makes a variety of trustworthy tripods starting with the Manfrotto BeFree and increasing in quality and price from there.