Decide what style or styles of dance you wish to study. Examine the other types of exercise you enjoy; this should shed light on the style of dance to which you're best suited. Think of the types of music you like to move to when making your decision. Seek out a studio that offers the style or styles of dance you've decided to study.
Make an appointment to visit the studio and talk to the teacher. Ask whether the studio has sprung wood floors or Marley floors, which help protect dancers' joints. See if there are mirrored walls, which are necessary to help students check their positioning and form. Look for ballet barres, if ballet is taught at this studio. Ask the teacher about her background. Listen carefully and assure yourself she is knowledgeable in the area of dance she is teaching.
Take a class at a few of the studios you've visited to find the teacher that best suits you. Some studios will let students take the first class free. Observe a class or two if you're not allowed to take a sample class.