Here is a few simple solutions based of my experience?
- Advertise a few specials on forums.
- When it comes to specials think out side the box.
- Try offering account credit instead of taking money out of your pocket.
- Ask your customers what they are looking for and what you can do to improve your services? You can use google forms or survey monkey.
- Use social media for advertisement specials.
- Some people use eBay but if I was you I would try to keep it to your billing system and off eBay.
- Buying some ad space on google, Facebook, twitter if you have the budget.