How to take your blood pressure at home:
There are different cuff sizes. Usually there is a range on the cuff, meaning if you put it around your arm, it should fall within this line for the most accurate reading.
Avoid things that will affect your blood pressure at least half an hour before taking it. Things that will increase it are smoking, caffeine, exercise or needing to urinate. Things that will decrease it are a recent meal or alcoholic beverage.
Chill for 5 minutes beforehand in a seated position. Support your back and feet (this can change the numbers 5-10 mmHg), do not cross your legs (this can change the number 5-8 mmHg), take a moment to do nothing and breathe (this can change the number 10-20 mmHg).
Place the cuff on a bare arm right above the bend of your elbow and keep your arm around your heart level. Do not talk (this can change the number 10-15 mmHg)
Elevated blood pressure does not often cause symptoms, which is why tracking it is important. Take one in the morning and one in the evening before eating. This is due to the variance that blood pressure will have throughout the day giving a better idea of your trend. Do this for two weeks.