Avoid caffeinated or alcoholic beverages, and don't smoke, during the 30 minutes before the test.
Sit quietly for five minutes with your back supported and feet on the floor. When taking the measurement, support your arm so your elbow is at the level of your heart.
Push your sleeves out of the way and wrap the cuff over bare skin. Measure your blood pressure according to the machine's instructions.
Leave the deflated cuff in place, wait a minute, then take a second reading. If the readings are close, average them. If not, repeat again and average the three readings. Don't panic if a reading is high. Relax for a few minutes and try again.