One week prior to your appointment stop taking any non-steroidal anti-inflammatory drugs (NSAIDS) like Motrin, Ibuprofen, Aleve, etc. as well as herbal supplements like ginko biloba, Vitamin E, fish oil, Omega 3, ginseng, St. Johns Wart. These may increase the risk of bruising.
Be sure your skin is clean and dry. You may use moisturizer, but not makeup/foundation.
Identify a well-lit, distraction-free area in your home with a chair where you can sit (the kitchen usually works just fine).
Do not drink alcohol prior to your appointment.