Follow your doctor's advice n how and when to take your blood pressure.Here are some important hints: 

1.Before Taking a Measurement 1.Sit quietly for about 10 minutes.This will allow your body to return to its normal,resting state.     

2.Take your blood pressure in a comfortable environment not too cold,not too hot as temperature may affect your measurement.

3.If you've just consumed beverage containing caffeine such as coffee non-herbal tea.or cola wait 30-45 minutes.Also,don't smoke just before taking a measurement.