• Measure your blood pressure several times a day at the same time each day because blood pressures vary throughout the day.
• Get duplicate readings separated by two to three minutes.
• Before you measure blood pressure, sit quietly and comfortably for about five minutes with your legs uncrossed and your back supported by the chair.
• Rest your arm on a table or desk at the level of your heart.
• Don't measure your blood pressure immediately after waking up in the morning.
• Don't eat, exercise, smoke, or drink alcohol or caffeinated beverages for at least 30 minutes before taking your blood pressure.
• Use the same arm each time you check your blood pressure.

via yahoo