Look for classes offered at the beginning level for older students in your area. Good resources for these classes are your local community college or learning annex, community groups such as the YWCA or YMCA, as well as traditional dance studios.
Talk to your future ballet instructor before signing up for a class. You should ask questions about how the classes are organized, as well as whether the class is truly for beginners. Some classes may require basic knowledge of ballet positions and may only be offered as part of a sequential series which builds on knowledge accumulated throughout the course.
Request information regarding the required attire for your prospective class. Visibility of the body in motion is essential to ballet teaching, so don't be surprised if you are required to wear a leotard and tights--though many schools do allow older students to wear less traditional garb, such as jazz pants and tight fitting T-shirts.
Select ballet shoes which fit your foot properly. Ballet shoes, even for the novice adult dancer, must fit snugly and remain securely on the foot throughout the dance movements.
Take time to warm up before starting your ballet class each week. Performing leg and torso stretching exercises can help to limber up tight muscles. Performing a little bit of cardiovascular exercise such as taking a brisk walk before class can help warm up your body while putting you in the right frame of mind for your class.
Look into ballet exercise DVDs or tapes if you are unable to find a studio or class for adult students. You can take up ballet in the privacy of your own home while learning from recognized professionals in this art form.