Listen to expert domainers on domainsherpa.com. Read anything by Michael Berkens, Frank Schilling, Eliot Silver, Morgan Linton, and Ron Jackson. Watch YouTube videos on domain investing. Read blogs like The Industry News Magazine at DNJournal.com. Search #domains on Twitter. Go to industry conferences. Understand the Google Keyword Planner tool inside and out.
The market-driven principles of the domain trade mean that a domain is only worth as much as the buyer is willing to pay. It is for this reason that criteria such as market potential and usability play such central roles in determining prices. Values can change at the drop of a hat. The price of a domain that was once of little interest to anyone in years past can skyrocket once, for example, a newly founded company takes interest in that same name.
Your course of action really depends on how much work and effort you can put into the expired domain. If you're barely able to maintain and optimize your current site, you probably want to just 301 redirect the old site (note: see my amended comment above about the link value not likely to be passed). If, however, you're more creative and have some time on your hands, you can try your hand at crafting a microsite. If you really know your stuff and are experienced at making money off various websites, you'd probably do well with the third option.
If your domain name is related to a particular niche, then you may find success by advertising in forums that are related to that niche. Simply placing a link in the signature of your posts can tremendously speed up the selling process. While it may be possible to find prospective webmasters on niche-specific forums, it is generally better to advertise on webmaster forums, where there is a high volume of potential customers.
If you are feeling ambitious, you can link each of your domain names to its matching “buy it now” purchase page at one of the marketplaces. Another more sophisticated option would be to “park” your domain with one of the leading domain parking companies, such as DomainSponsor or SmartName and enable their built-in “for sale” message and contact mechanisms.
Please keep in mind that domain flipping isn’t child’s play. As much as you may want, it isn’t easy to buy and sell domain names for huge profits without putting in a good amount of time and effort. Although there’s nothing wrong in aspiring for at least one big deal per month, be aware that sometimes it takes months and months to sell just a single domain name.
Once you have a name in mind, how do you know if the price is fair? I like to use namebio.com to compare the domain I’m thinking about buying with similar domains that have sold. You can enter the keyword and also use some advanced search features to see a list of names similar to yours, what they actually sold for, and when they sold. You can also research current domain sales on venues like GoDaddy Auctions and Afternic. Finally, Ron Jackson issues a weekly report on DN Journal that covers the top public sales of the week. You can use all these resources to help you price your domains correctly.
They see a domain’s price tag and they can instantly tell whether it’s under or overvalued. This is probably the most important skill one should have in this industry. Neil Patel has an interesting related quote: “The most important thing to remember when buying sites is that you always make money on the buy, never the sell.” In order to successfully do this, you must be able to spot undervalued domains. This is what will ultimately translate for you into a handsome profit margin when you get the opportunity to resell the domain for its “real value”.