Every search online originates with someone typing a word or phrase into the search bar of a search engine. It doesn't matter if it's Google, Yahoo, Bing, etc. every one will use this method to find a product or service online. As an online marketer you can use this knowledge to make a dramatic impact on the amount of exposure your website gets.
You can find the keywords that are 'hot' for your particular niche and then use those keywords in blog posts, articles, and even in the tags on your website to make your site stand out in the search engines for that keyword phrase.
To really make this process work you have to first start with the right keywords. Ideally, you'll want to find a list of keywords that have a lot of monthly searches without a lot of competition. Now, there are a lot of theories as to how many searches a month constitutes 'a lot'. Some will say that any keyword that gets at least 1,500 searches a month is a lot others say you need a lot more than that.
No matter which school of thought you graduated from one thing is clear: the more searches a keyword phrase gets the higher the competition will be and the harder it will be to rank for that particular keyword. That's not to say that you shouldn't try it (many online marketers really don't know that much about using keywords effectively so you can rank well for a competitive keyword if you know what you're doing).
The biggest favor you can do yourself is to learn the skills needed to fully optimize your keyword marketing strategy. Knowledge is power and no where is that more true than online. Learn the tricks to finding those keywords that will bring all the qualified customers to your offers that you can handle and you can make money for the rest of your life.
There are many keyword tools you can use to start your great keyword treasure and some of them are free. The most popular free keyword tool is the Google Keyword Tool. With this tool you can start with a broad search of a particular keyword and then drill down to find some less competitive keywords that you can use in your marketing efforts.
Please don't set yourself up for failure by not taking the time to properly use keyword marketing techniques to drive a lot of very qualified traffic to your website. If you learn to do this you will never have to pay for traffic again.