There is no one good way to monetize your website. Rather, it takes some thought as to what would work best for your particular website.
For instance, my Bible Treasure Hunt website is designed specifically to sell a product I created. I might include a few ads here and there... maybe create a couple of Bible Treasure Hunt t-shirts... but primarily the website's monitization is through the sale of my Bible Treasure Hunts. If you have a website specifically to advertise your self-published books, you probably won't need to worry too much further about monetization.
This Indie Writer website, along with My Big Redneck Website, on the other hand, are monetized in several different ways. It is always a good idea to include Google AdSense on your websites, as this is such a quick and easy way to make money. You add a few snippets of html, publish to the web, and every time someone clicks on one of the ads, you get a few cents. Once that adds up to $100, Google sends you a check. Can't beat that, right?
Another way to monetize your website is to become affiliates of companies that sell products that coordinate well with the subject of your website. For instance, this Indie Writer website affiliates strongly with GoDaddy, not only because they relate so well to indie writing and website design, but also because I have such a great long-term working relationship with them, and I can make upwards of 30% of GoDaddy sales made through this site simply by placing a few ads on my website.
The Amazon Affiliate Program is another old standard a web designer might consider, since they offer products of every kind. Just sprinkle a link here and there on your website. The customer does not have to purchase that specific product for you to get credit. You get paid for anything they purchase within a specific time frame of visiting Amazon.com through clicking on your link.
If you would like to offer more products and get paid in a single check, you might consider LinkShare's Affiliate Program, where you may sign up to become affiliates of multiple companies in a few easy clicks.
If your website lends itself well to t-shirts, you might try your hand at designing a few and then becoming an affiliate of CafePress, where you'll not only receive commission for your t-shirt design, but also for every t-shirt you sell through their site.
Be creative in monetizing your website. Try several approaches and see what works for you.
Monetizing Your Website