There are four ways to make money directly from a website
1. Sell a product or service directly to the visitor via ecommerce.
2. Place click through ads, such as Google AdSense, on the pages of your website and get paid every time a visitor clicks on one of the advertisements.
3. Become an affiliate advertiser for other companies and receive a commission when someone goes to their website via your website and then consummates the purchase of a product or service. There are a few companies that specialize in providing affiliate marketing programs. One of the best is Commission Junction.
4. Sell advertising space on your website to other companies.
The first three methods are quite obvious in their implementation and methodology.
Having a product or service that can be purchased directly from your website is in my opinion one of the primary reasons that the Internet should exist. There are some notable names in the sale of products on the Internet, companies such as Amazon.com have expanded their products from books to a vast array of items, and Amazon.com does not have a retail affiliation. Cooking.com is another very successful Internet retailer, offering tens of thousands of items, without a retail storefront. Most of the big retailers, such as Sears, Home Depot, and Lowes have an online storefront. Amazon.com, Cooking.com, and Home Depot also have affiliate programs in place to drive potential buyers to their websites.
Google AdSense and Commission Junction are examples the second and third methods, namely click through ad placement and affiliate program companies. These companies will accept most websites into their programs with the normal exceptions of websites that are designed for fraud, hatred, racism and/or are sexually explicit. Both of these companies publish their terms and conditions on their websites and although I have not investigated every ad placement or affiliate program company, I would think that they all have similar exclusions. There are two primary differences between the programs. With click through ad placement you have little control over what ads will appear on your website, however you do earn revenue every time a visitor clicks on an ad, whether they place an order with the advertiser. With affiliate programs, the visitor must not only click on the ad that appears on your site, but they must consummate a transaction of some sort. Commissions are substantially higher in an affiliate program then with a click through program, but you are subject to the advertiser "selling" the visitor on there product or service in order to receive compensation for placing their ad on your site. Whether you use a click through program or an affiliate program the higher your website traffic the more money your website will earn for you.
The forth method, selling advertising space directly on your website to other companies can be a much more difficult to implement than the other three methods, but on the other hand it can be much more rewarding - financially. The two challenges are finding companies that would be willing to pay for a position on your website and what advertising fee to charge. If your website becomes noted, companies will come to you, however that requires a relatively high level of traffic. You can go out looking for companies that you believe would be interested in advertising on your website. To attract an advertiser there has to be some sort of relationship between your company and the company that you are trying to obtain advertising from, in other words a common set of visitors. As an example, if you offered small business accounting services then a likely candidate would be a small legal firm that would be interested in providing legal services to your clients. Your businesses are complimentary. The decision that has to be made at this point are you better off to trade banners and attract each other