Inprove your diet, cut out food which you feel dramatically increase salt in your blood (ie crisps, or 'chips' to Americans
). Get exercise, but not so much that you drive yourself into the ground. Also, try to eat less fatty foods.
There is truth in Timber's claim. Red wine is one of the best drinks.
Of course, this is just from my limited knowledge of high blood pressure, so you will definately want to consult a doctor on this.