Once you have a site up that is regularly updated and gets a steady amount of traffic, you should start thinking about monetizing. The list below provides ways to monetize that won't take up a lot of your time, so you can focus on building your site with good content and growing your traffic. These are the most basic (and arguably the least profitable) methods, but they are effective interim monetizing strategies.
As with most strategies regarding money, diversification is key. Try a combination of these methods to maximize earning potential (without making your site too ad heavy). Play around with your layout, if it's flexible, to give different ads more or less exposure (don't let them overshadow your content). Test a variety of networks. Make sure you are being paid accurately and in a timely manner.
Monitor your performance and if you are not happy with the service or results, try another company.
1. PPC Ads (Pay Per Click)
Google Adsense is the most popular and widely used option. They serve contextual ads (image or text) based on your content, and pay when someone clicks on the ad. How much you make on Adsense depends on several things. First, advertisers bid on keywords, so if you happen to write about a topic that has high paying keywords, then each click will be worth a lot more than another topic with low valued keywords (keywords that has really low bids). Also, people who came to your site from search engines are more likely to click on these ads than people who are repeat visitors. It makes sense then to spread out your Adsense ads to provide easy access for search visitors.
2. CPM Ads (Cost Per Thousand)
Unlike CPC ads, CPM ads pay per impression. Viewers don't need to do anything for you to be paid. You just need to serve the ad to them. The downside is that you're paid almost nothing for each impression. Rates can go as low as $0.10 per thousand impressions. But it's still a good option to use in conjunction with CPC ads. CPM ads can be placed in less prominent spaces (below the fold) whereas CPC ads should have better position. Most ad networks that offer CPM ads have CPC ads thrown in as well. You can set your own prices and remove unappealing ads.
3. CPA / Affiliate Ads (Cost Per Action)
CPA ads pay per action. Viewers don't just need to click on them, but they actually have to do something, either sign up/register or make a purchase. Not surprisingly, they are the highest paying ads. However, how likely your visitors will click on the ad and perform the desired action will depend very much on how relevant the ad is to your content. For example, a site about digital photography may do very well showing digital camera CPA ads. Some sites are much better suited for CPA ads. Consider whether any CPA ads would add value to your visitors.
4. Text Links
Text links work the same way as the above. You set aside a space on your page and text links will start showing up when they are purchased. You need to submit specific pages into the inventory, so enter your most popular pages (homepage, category pages, and very popular articles). Rates are based on your PR, which has to do with how many other sites link to your page. If you often get linked and mentioned, text links may be profitable for your site.
5. In-text Advertising
In-text ads don't require any additional real estate, which is attractive to many site owners. Ads are attached to text in your content, showing up as underlined or double underlined words that are clickable. Some will pop up a little advertisement when the word is moused over. Many viewers, however, find these ads distracting.
6. RSS Feed Ads
Offering a feed of your content is essential. More and more readers are using feeds to catch up with their favorite sites, and not offering one will alienate a lot of readers who would be interested in your content. There is yet to be a lot of advertising options within feeds, but for now you can still monetize the traffic to your feed.