It is a necessary part of business and begins with a simple question: who is your target audience? Once you know which people or companies need what you are offering, it becomes a matter of putting the name of your product in the places where people who fit the buying demographic go, whether that's other web sites, radio stations, or newspapers. Each ad should revolve around a central theme, the aspect of your business you believe makes it stand out from competitors, and that message has to be repeated consistently. Studies show people have to be exposed to a thought, pitch, or idea several times before it has any impact.

The benefits and disadvantages of advertising often come down to the same thing, money. Ad dollars allow you to reach a large audience at a relatively low per-person cost. However, those per-person dollars added together can be a significant amount. Your budget is also a guide to how many different media you can use, but keep in mind that experts recommend that if money is an issue, reduce operating expenses instead of marketing dollars.

Back to the initial paragraph and going where your potential customers already are. There's a reason truck makers, beer companies, and action-movie producers buy ad time during football games - those viewers are also their most likely customers. So, where do you place your product? As a rule television and newspaper advertising are expensive and neither allows for a narrowly-targeted market. However, if your product has broad appeal, they reach the widest audience. Radio provides a more segmented approach in that different formats cater to people of differing income levels, interests, and spending habits, allowing you to put your product before those likely to be interested in it. Direct mail or email allows for selectivity as well, but there's also the threat of your flier being treated as "junk mail" even though the recipient is a potential buyer.
There has been a surge in the number of special interest magazines on the shelves, appealing to people with specific interests. Taking that route, though, means your ads will appear alongside your competitors and could get lost in the shuffle, so they have designed in a manner than will make them stand out. Placement in periodicals or on web sites that cater to related interests can be beneficial. For instance, if you sell photographic equipment, have a presence in a travel magazine or an agency's site since people who take trips tend to want pictures; a florist or china maker would fit into a bridal magazine; and, tools or trucks have a place during a television program geared to the outdoorsman.
Advertising can be time-consuming and doing it yourself means less opportunity to focus on your core business, so it should be something you outsource. Agencies and media outlets have creative people and their talent is in part what you're paying for. Certainly, you will want to offer input as to how your ads look or sound, and you will be the final arbiter as to what media are utilized. It's one thing to pay for the creative process, it's another to let someone else dictate how your dollars are spent.