Eco holidays or green holidays can be luxurious and this article shows how great being green and eco for your holiday can be.
Green Eco Travel - 7 Luxury Eco-Retreats
Let people know if you have some eco green elements to your accommodation. Solar water, solar electric, wind turbine and wood stoves etc. Even if all your products are Fair Trade and Organic let people know as this could sway them to booking their holiday with you over someone else.