You could try offering a reduced sale price for bitcoin transactions or maybe a small free gift aswell as adding a simple step by step guide or link on what bitcoin is and how to use it
Hope this helps.
This is very good advice. It is likely that a lot of your potential customers do not know about and/or have bitcoin, and if they are offered a discount for using it then they likely would.
It would also help if you were to advertise on bitcoin related sites (I am not sure if it is acceptable to make an ANN thread on here if your site simply accepts bitcoin).