If you only have a slight blood pressure increase, it is often enough to start by changing your lifestyle. It may not affect the pressure itself all that much, but it can reduce the risk of cardiovascular disease.
Blood pressure is affected by your weight, so it might help to try and lose some weight (it's hard, we know). A weight loss of just a few kilos can lower both the blood pressure and the levels of blood lipids and blood sugar, which together reduces your overall risk of cardiovascular diseases, such as stroke or myocardial infarction.
Regular exercise such as walking, cycling or swimming has also been shown to lower the pressure somewhat.
Lastly, cutting down on your alocohol usually leads to a clear reduction in blood pressure as alcohol consumption, especially excessive alcohol consumption, is a common and often underestimated cause of hypertension.