First, you have to determine WHY your blood pressure is low; then treat the cause. Some patients naturally have lower blood pressure. I have several patients with normal systolic (top reading) blood pressures in the 90's.
Are you having symptoms with your blood pressure being "low" and what is "low" to you? For some "low blood pressure" can be below 110. It is very individualized and should be reviewed with your medical provider for more answers.

Low blood pressure may be a sign of electrolyte imbalance and/or dehydration. Make sure you drink at least 2 liters of water a day.