You can dramatically increase your visibility when you begin to write articles in your domain specialization distribute them to editors as free content for their e-mail newsletters for their websites.

Just ask that a link to your website and a one-line description of what you offer be included with the article. This is an effective "viral" approach that can produce hundreds of links to your site over time.
You'll find lots of information on how to do this from the most popular article marketing site, EzineArticles.com. When you create a free membership account, they begin sending you instructions and ideas each week.

Become Part Of A Social Media Community.

Some of the best online communities for business include Facebook, LinkedIn, and Twitter.
In addition, you may want to participate in a social bookmarking community in which members share with each other information about websites, articles, or news items that they like (or don't like). These include Digg, Delicious, StumbleUpon, Google Bookmarks and so on.
Search engine spiders troll these sites looking for links to something new and relevant. You can usually place a link to your website in your profile, but the biggest gain comes when other people mention you (which generates traffic to your site), link to you (which increases your PageRank and brings traffic), or bookmark you (which increases your PageRank and brings traffic).
NOTE: Do not join a community to spam them or talk incessantly about your business. Like any community you must listen, comment, and make a genuine contribution for the good of others.
If you attempt to spam a community or hog conversation or any other obnoxious behavior then it’s very likely that the community owner will simply boot you out of the community altogether. Self-serving links and comments will always hurt your reputation in any community.
All communities run on trust.  Trust takes time to build and can get destroyed in moments.  Build connections is a community based on trust and work really hard to keep it that way.
By the way, to get started, why don't you visit my social media pages and become a Facebook 

Publish An E-Mail Newsletter.

This does require a commitment of your time, creating a monthly or better yet bi-monthly e-mail publication is a really important promotion techniques.
It could be a newsletter ("ezine"), list of tips, industry updates, or new product information -- whatever you believe your readers will appreciate. This is a great way to keep in touch with your prospects, generate trust, develop brand awareness, and build future business.
It also helps you collect e-mail addresses from those who visit your site, but aren't yet ready to make a purchase.

Ensure A Signature To All Your E-Mails

Email signatures help potential customers get in touch with you.  Most e-mail programs (I use Thunderbird) allow you to designate a signature that appears at the end of each message you send out.
Limit the signature to 3 to 4 lines: URL, E-mail address, Gtalk ID, Skype ID and one-phrase description of what your website offers.  

Aggressively Ask For E-Mail Sign-ups.

If you want subscribers to your e-mail newsletter, you have to work hard at it.
Include an Email subscription form on every page of your website. Promote sign-ups through free whitepapers, e-books, or other products.
If you have a local business, perhaps you can ask your customers to sign up to your e-mail list to get special Internet only offers.
Ask your business associates when they give you a business card if you can send them your e-mail newsletter.
Do personalize the newsletter (and the e-mail subject line if possible) with the recipient's name. It does help when building a relationship.

Send Transactional And Reminder E-Mails.

A transactional e-mail is sent to an existing customer to initiate, remind, confirm, or thank the individual.
Be creative. If you keep careful records, you can send e-mails to customers on their birthday to remind them to return to your site.
Subscription confirmation e-mails can also mention several popular products. You might remind customers that it has been three months since their last order and ask if it's time for a refill.
Thank you for your purchase e-mails can offer a coupon to bring your customer back for a future sale. Use your imagination, but don't pester your customers. You're there to serve them, not the other way around.

Send Offers To Your Visitors And Customers.

Your own list of customers and site visitors who have given you permission to contact them will be your most productive list.
Send special offers, coupon specials, product updates, and so on to them.  This often initiates another visit to your site. If you have a regular newsletter, you can include many of these techniques in your regular e-mailing.

Announce A Contest.

People like getting something free. If you publicize a contest on your website, you'll generate more traffic than normal.
Make sure your prizes are designed to be attractive to individuals who fit a profile which describes your best customers.  You do not really want to be handling out prizes to just anyone at all.  The prizes should in turn result in a modest increase in business or this technique is not working.  

Rent Targeted, Commercial E-mail Lists.

The direct marketing industry has developed targeted e-mail lists you can rent -- lists consisting of people who have agreed to receive commercial e-mail messages.
These lists can cost between $40 to $400 per thousand or 4¢ to 40¢ per name. Do a small test first to determine the quality of the list.
A great approach is to find an e-mail list broker (www.google.com/search?&q=e-mail+list+broker) to help with this project. You'll save money and get experienced help for no additional cost. Realize, however, that due to the high cost of renting lists, many businesses won't generate enough business to justify the cost. Run the numbers before you invest heavily in this technique.