We can define monetize as in, to establish a legal tender for the purpose of making money or turning debts to liquid in the economy. Buying domains do have costs such as renewal fees, hosting, labor and time spent on them. These are over heads hovering over the cost of buying and selling domains therefore a domain should be a money making scheme rather than a cost while waiting for its sale. youtube monetization is a good example of video production money making scheme offered to anyone.
monetize definition is beyond the above short definition, however the above is concentrated on monetize meaning and monetization from a domain angle as explained previously.
The techniques involved is your imagination and dedication to the subject and area of the domain. Making a website and putting advertisements such as pay per click doesn't guarantee a good turn around especially if the website built is related and targeting a single keyword. Some may argue targeting a niche marketing might be a good idea which I totally agree but the point to make here is that targeting a niche doesn't mean targeting a single keyword.
Choosing the correct advertisement network is the most important factor for monetizing however targeting the domain audience is even better choice in a long run but this will take the project outside the scope of monetization to full website development.
The following some techniques I found useful and used by lots as follows:
1- Quickly develop the site to a target audience choosing the right keyword
2- Selecting the ad network that is suitable for the domain, example, if your visitors are going be flown from outside the search engine then there is no point putting Google addsense because Google won't pay for clicks that are not traced from the search. However if you have killer keyword in your domain and you are not willing to pay to get visitors then pay per click might be a good a choice. Amazon is a better options if your traffic is going to be gained from forums and advertisements because you only get paid if a click has converted to sale. Check with the network as products and offers keep changing all the time. Example Google also has products to get paid per conversion rather than per click.
3- Get to know the subject or spend money on content writing by someone who knows the subject and slowly develop the site as if you are not going to sell it.
4- Monetize a blog/website a video by placing advertisements on them. Don't ignore social network in your marketing techniques. I have just recently discovered the power of social networks.
Parking your domain
Parking your domain with a domain parking service that enables you to earn money from your domain natural traffic. This is the worst option however it might be the best option while you are waiting to develop your site. Parked domains are not indexed by the search engines and they seldom generates the desired income. The lucky domain will generate just enough to pay for its keep. In very rare situations a domain will generate good traffic where a domain is a common error spelling or another famous site in another extension is exact match to your domain.
Keep reading and searching for information, explorer affiliate programs and develop websites around both your target audience and the affiliate products. Only promote what you can honestly describe and feel right about. Some products are just not a good deal for your customers and If you don't use the product for yourself or recommend it to someone you love then don't promote it to your visitors. Users are not stupid and they always check before they buy, well at least the majority of customers buy what they want rather than what you have.
Good luck with your Monetizing experience because it is not as easy as you may think nor it is very hard to achieve.