FORTUNE — Dear Annie: I recently left a 26-year corporate career to start my own consulting business, with my former

employer as my first client. A friend sent me your column about how to drum up new business, and I’m doing everything it suggests, but I also wonder how to make the most of the Internet in getting the word out about my services. So far, I’m just using LinkedIn, Facebook, Twitter, and a blog, but there must be more I could be doing online if I just knew where to start.

Also, how should I handle negative comments on my blog? When people make nasty remarks about points I’ve made, should I respond and get into a protracted argument, or just ignore them? — Flying Solo

Dear Solo: “A lot of people are singing the praises of online marketing and social media these days, but much of it is just a bunch of hype,” observes Patrick Schwerdtfeger, a serial entrepreneur who now heads the Entrepreneur and Small Business Academy, a nationwide network of small business owners based in Berkeley, Calif.

“A few businesses, however, really are using the Internet to explode their revenues practically overnight,” he adds.

How? Over the past seven years, Schwerdtfeger says he “tried everything” to build his own ventures’ credibility and exposure. “Some of my efforts succeeded. Most didn’t,” he admits.

To spare other solo fliers that trial-and-error approach, he has now collected his experiences in a book you might want to check out. Called Marketing Shortcuts for the Self-Employed: Leverage Resources, Establish Online Credibility, and Crush Your Competition, it’s organized into 80 short chapters, each with step-by-step instructions on a different brand-building move.

Happily, most of these tactics are cheap or free and take less time than you might expect. For example, Schwerdtfeger suggests, “Contribute 50 intelligent comments on relevant industry forums. Offering a quick piece of advice on a forum is easy and can be done in 10 minutes or less, so you could accumulate 50 of them in a couple of days.” Include your phone number or email address in your forum signature.

A more in-depth approach to positioning yourself as an expert in your field: Publish articles online, through low-cost services like iSnare and EzineArticles, and include a link back to your website or blog.

The articles needn’t be longer than 500 to 700 words, Schwerdtfeger says, but they should be packed with enough insight so that people who come across them through a search engine will want to hear more from you and will click on the link at the end.

Don’t worry that giving away information online will make prospective customers less inclined to pay for your services. Instead, it’s more likely to prime the pump. Schwerdtfeger tells of a dentist in Boston, for example, who gave away a 20-page e-book called “Healthy Mouth, Healthy Sex” online for free — and attracted so many visitors to her web site, and ultimately her office, that her annual revenues shot from $150,000 to over $1 million.

You mention that you’re already active on Facebook. If you haven’t already done so, Schwerdtfeger suggests you start announcing your blog posts on your Facebook page and using the “Facebook comments” plugin to encourage interaction with readers.

And what if, as you note, some of that interaction takes the form of snarky comments? Always respond to those, Schwerdtfeger recommends, but wait 24 hours first, to give yourself time to cool off. “Answer negative comments as best you can, but there will be some individuals you’ll never be able to appease,” he says.

“The important thing to remember is that your response is only 5% intended for the person who’s carping at you. The other 95% is intended for all the other people who will read the original comment followed by your response.” In other words, letting the exchange deteriorate into a virtual shouting match will just make you look hot-headed and unprofessional.

Schwerdtfeger has dealt with his share of hecklers, and he says he tries whenever possible to see potshots as a chance to learn something. A case in point: A “vicious” comment from someone about a podcast he recorded back in 2006 made him realize, once he thought it over calmly, that he wasn’t giving enough hard data to support his conclusions.

The criticism came after the podcast’s fourth installment and, says Schwerdtfeger, “If you listen to the whole series, you’ll notice that, starting in the fifth installment, my statements are backed up by a lot more supporting evidence. In other words, the later episodes are better than the first four.”

The moral of the story: “Ironically, sometimes negative comments are the best thing you can hope for. They tell you how to improve.”

Talkback: If you’re using the Internet as a marketing tool, what have you found to be effective and what is just hype? Leave a comment below.