If you’re serious about domain flipping, one of the best strategies is to buy expiring domains that auctioned on the market such as GoDaddy Auctions. Make sure you pick domain names that have good traffic, backlinks and SEO metrics, or domains with the generic niche. Expiring domains with a potential for profit can be found using BuycomDomain.com, this is a free website/tool that helps you sort through the domains by different metrics (age, traffic, backlinks, domain authority etc).
One of the easiest ways to make money online is by buying something for a low price and selling it for a higher price.  It is even better when you don’t need to pickup or ship a product.  Today I’m going to talk about how to make money online by flipping domain names and how I personally have made tens of thousands of dollars in the past year doing this.
The IP popularity and domain popularity each play a part in the overall quality evaluation. If you come across an expired domain with a high link popularity (i.e. a large number of backlinks), but then poor values when it comes to IP and domain popularity, you can assume that these links were obtained in an artificial way. Domains like these will have already caught the search engines’ attention. Perhaps this is the reason why the domain was abandoned. Users that want to start a serious online project should steer clear of these domains.

Most domains traders, or resellers, buy hundreds of domain names. This way, the chances of hitting the jackpot are higher. But, this takes some up front money. You can start with a handful of names and work your way up. This is the best way to begin. You may also decide to purchase a name from another seller if you think that a name will be big enough.

Domains that are indexed on Google and highly ranked are particularly attractive to traders. Other SEO aspects, such as backlink profiles or the search volume of the keywords in domain names, also play a significant role in appraising value. Design can also positively affect the price of a domain. Short and succinct names that are easy to remember are especially advantageous. Endings are further factors that should be taken into account. Top-level domains (TLDs) such as .com or .org are by far the most sought-after endings.
@ib2 @T-3D I've been a domain investor for over 10 years and have been very successful at it. There's a lot more that goes into it then just registering a domain name and hoping it will sell. You can list your domains on Godaddy auction listings or on premium listings, I've had a lot of success with those. Some good resources are namebio.com, dnjournal.com, namepros.com and others.
Acquiring what you believe may be a valuable domain name is the easiest part of the equation.  Finding the right  buyer is much more difficult. Using auction sites and forums is perhaps the best way to find qualified buyers that are interested in your domain, and using auctions will take some of the stress away from establishing the value of a domain name yourself.
Length: This is pretty self-explanatory. Generally the shorter the domain name, the more valuable it is. This difference in value decreases exponentially as the name gets longer, though. For instance, the difference in price between 3 and 4 letter domains are significant, while the price difference between a 7 and 8 letter domain would usually be much less significant.