1. Improve Customer Service
Customer service is a form of advertising, so always keep these skills honed. That means answering your emails, being polite, likeable, professional and ethical. Not answering emails sends a horrible message of unprofessionalism and simply not caring about the person who is emailing you.
2. Use Others' Facebook Pages
Use other people's Facebook pages. There are lots of Facebook pages that promote other people's products.
3. Get Free Business Listing
Get a free business listing with Google Local.
4. Use Free Offline Networking
Seek out free networking events in your area, utilizing groups like 'Meetup' etc.
5. Create/Offer Loyalty Incentive Program
Offer a loyalty program or exclusive incentive to your loyal customers and gain some new customers in the process.
Actively take part in forum that relate to your business.
7. Show Customer Appreciation
Don't forget your customers. Customers who feel appreciated are going to give that appreciation right back to you. Send them and email, or yearly birthday card and interact with them in whatever way you deem fit and professional. The goal is to let them know they are important.
8. Never Forget Current Customers
In your quest to always find new customers, do not make the mistake of forgetting current customers. Keep those ties open. Current customers often become repeat customers, so never push them aside in your attempt to garner new ones.
9. Market With Articles
If you like to write consider writing articles and submitting them to sites that accept articles. This is a great way to obtain more exposure, traffic, readers and potential buyers. Here is an awesome list of the top 50 article directories.
10. Give 'Em Something
I'm not saying to "give away the store", but on occasion, giving away a little somethin' somethin' is a nice reward to customers. You can create coupons like refer-a-friend coupon, happy customer day coupons, etc. You decide when you want to give it away - perhaps during the holidays, or some other holiday, perhaps on your birthday or your site's birthday. This is a great incentive but be careful with how often you do it. If giveaways are done too often then people may come to just look for the giveaway and negate everything else you've got going on so you determine when (and if) you want to engage in such an activity. Good luck!