Breastfeed, breastfeed, breastfeed! Every time your baby empties your breasts, your body gets a signal to make more milk. Breastfeed before every supplimental bottle you give her. Put her in a sling next to your breast and let her nurse as often as she likes!
The advice below is great. Eat lots of oatmeal, drink lots of water, balance your meals as well as you can with a newborn! And the beer one works. My Granny was given Guinness at the hospital when she had my Mum.
I responded well to "Mother's Milk" tea, which had Blessed Thistle and Fenugreek in it. For the first few days, have a cup about every 4 hours, then twice a day.
The Massachusetts Breastfeeding Coalition has a page on their website called "Making Milk is Easy". It can be found at:
http://massbfc.org/parents/milk.html
If you find that you need more help and advice, you can find all of the local breastfeeding resources near you (I think this is in MA...didn't see where you are from) at ZipMilk.org. This great new resource has a list of LLL leaders, Lactation consultants and WIC breastfeeding counselors. You enter your ZIP code and all the local helpers pop up.
Hope this helps. Congrats!