Great question (and a commone one!)
Diet and lifestyle changes are probably the biggest factor. Meds can be used to get your BP down before it causes too much damage, but it's better to address the issue without medication over the long haul.
The first step is to start getting educated, as you are now. I recommend joining the Yahoo! bloodpressureline group for more good information and a receptive group (including a great doctor who specializes in the control of hypertension
I think it's important to monitor your BP regularly (at least daily) and then start trying the most likely changes:
1. Cut back on sodium intake (it's actually pretty easy).
2. Increase potassium intake (bananas and oranges, among other fresh fruits)
3. Reduce BMI to < 25% (this is huge). See the DASH and Rice diets.
4. Get regular exercise (6-7 days/week)
5. Quit any of those nasty habits such as excessive drinking, smoking
6. Make sure you don't have sleep apnea
7. Have your vitamin D levels checked (they are chronically low in our society, and such low levels can cause a host of problems).
The list goes on!