Massaging the scalp daily can help, as it stimulates blood flow. There are also a few herbs you can try.
Cayenne is amazing at stimulating hair growth and helping you to maintain a healthy scalp. Just rub about 1/2 teaspoon of it into your hair while showering (be very careful to not get any into your eyes).
Fenugreek tea may also help, as it is an herb that is know to help increase circulation.
Also, look into your diet and lifestyle. Are you getting enough sleep? Are you drinking enough water? Are you eating a lot of processed foods? All of these factor into scalp and hair health.