The first thing I suggested for my company was to put "Please Recycle" on our marketing pieces. We also have recycle bins all over the office. You might try having a contest ( with some sort of prizes) for the best 3 suggestions for going green. Another way is to ask your customers to make suggestions for your business. That way, you can maintain contact with them and engage them in your going green program. You might like this article from Time too...
Hope that helps.