If you have a website then you should think carefully about how and where you advertise. It is important not to keep chucking money after money on marketing avenues that simply do not work for you.
If you are looking for quick results or are a relatively small company struggling to compete in the organic search results then you may consider Google Adwords.
Google Adwords is a program that allows you to create ads to display online. These ads will direct traffic to your website, whether it be the home page or a specific product or service you wish to promote. Once your ad is clicked on you will be charged a fee (depending on how you have set up your campaigns). Each click to your site will result in a fee regardless or not as to whether they end up contact you or making a purchase. For this reason it is important that you try and only target those that are genuinely interested in your products or services.
The program is immense and there are many options within it that allow you to target a very specific audience which in turn will keep your costs down and conversions high. Ideally you want to split your campaigns down into smaller ad groups which will allow you to make the ads very specific to the keywords.