For me it has been the following and it has worked wonders to the point that my doctor is likely to lower my BP medication next month if I keep it up:

.Added magnesium tablet before bed
.Conscious effort to eat foods with potassium in it...sulfite free apricots, potatoes now and then
.little to no sugar
.added a green juice most mornings...kale, spinach, cucumber, celery and a small amount of lemon and broccoli

For me, my blood pressure starts dropping within three days do doing this. Within a week, if done consistently, my BP will drop by several points...and if I keep it up, I have to lower my medication. Sadly, I messed up for the holidays.
But, I'm going back. I kept records before and within three days I actually felt a little woozy on my meds...as if I was taking too high a dose of my BP medication. I see the doc in January to discuss this. I had emailed her my numbers and she and her partner were amazed. I personally think magnesium and potassium are key, as well as the avoidance of sugar and salt (I was basically avoiding salt anyway).

I'll probably add the Morton's cream too!