Create a marketing foundation.

This may sound like a boring task, but it is essential to getting your ad campaign ready, Seda says. So, write down your marketing foundation, which includes:

Identifying these will help you choose high-performing keywords. This overview also will give you copywriting ideas for ad listings and landing pages. And, yes, that means writing a mission statement for your company if you have yet to do so.

Choose popular and narrowly targeted keywords.

This is crucial. Type one of your keywords into Overture's free search-term suggestion tool (www.content.overture.com/d/USm/ays/), to see the related phrases that include your keyword, and how many times those phrases were searched last month.

It's natural to want the keywords with the highest potential traffic. But hold on. You don't want to end up buying junk traffic. "Insurance," for example, can refer to "health insurance," "auto insurance" or "life insurance." Unless you offer all forms of insurance, the single keyword could bring the wrong audience (expensively so) to your site. (On a spring day in 2004, the bidding on "life insurance" was at $8.20 per click, a seemingly steep price, but the payoff might be well worth it to the competing advertisers.)

Likewise, "travel" and "tickets" are expensive keywords not likely to perform for your business. Phrases such as "discount airline travel," "cruise vacations," or even "Alaskan cruise vacations," are more targeted and will perform better.

Write compelling ad listings.

What sets you apart from your competitors if you're all bidding on the same keywords? Your ad listing.

Write an ad title and description that includes a benefit that your business provides to clients, and offer an incentive. Study your competitors to create a more persuasive call to action. For example, if all auto insurance quote providers promote "Reduce your car insurance rates – get a free quote," then you should be able to attract more attention with a few more details: "Save hundreds of dollars on car insurance – free rate comparison quote."

Make sure the keywords you bid on are in your ad copy. Your ad will appear relevant to users' searches, which help you achieve a strong click-through rate.

Use landing pages on your Web site to close the deal.

Once ad viewers have done a keyword search, read your ad and clicked on it, they're a step closer to becoming your customers. The page they land on plays a significant role in whether they move into the ordering process, or leave your site.

Don't send people to your home page. They've been promised something specific in the paid listing, so take them to the page in your site that gives it to them. That means either a product or offer page, or a special landing page designed just for that ad. Many businesses create a special landing page just for search-engine ads, Seda says.

To invite the sale further, put all critical information "above the fold" of the landing page. "You need an information-rich page," Seda says. "Put whatever you've mentioned in the ad listing right on the page, making it easy to see." Reducing navigational choices on your site also can be helpful toward closing the sale, she says.

Test, test, and then test some more.

With the variety of bid management and tracking tools available today, you're able to see your results immediately. (Check out Microsoft FastCounter Pro , which tracks Web site traffic and conversions. Some search engines also offer conversion tracking services.)

Because you can change your keywords, ad listings and landing pages at any time, you have impressive control over the performance of your advertising campaign. You can delete components that aren't delivering sales. You can swap out ad listings and landing pages monthly to promote new offers.

Simply launching a search-engine ad campaign will drive traffic to your site instantly. Then you can continue tweaking your paid listings in an effort to improve your leads or sales at the lowest cost per customer.

Watch your budget!

You must monitor your pay-per-click campaign regularly, Seda says, to make sure you're getting results and not burning through cash faster than you expected.

"If an advertiser is paying $300 per month for the clicks, and not seeing any sales, that is probably a bad investment," Seda says. "It could be that the product or service isn't right for marketing on search engines, but it's also likely that something in the campaign isn't working." Try different tactics, perhaps a change in your keywords and/or ad copy, to improve the quality of traffic and increase your orders, she advises.

Pay-for-placement advertising has been called by some the most effective method of direct marketing today. "The results are immediate and very profitable for a lot of businesses," Seda says. "Those are two chief reasons why it's becoming a mainstream advertising vehicle."