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.
Domain name sellers are advised to use to list their domain name. The real advantage with is the mandatory escrow service that comes with every transaction. The site charges the seller a commission of 15% per transaction or USD 50, whichever is higher, for domain names featured on the site. Sellers who do not list with but would like to use their escrow service will have to pay the minimum transaction fee of USD 50, or 3% of the transaction, whichever is higher.
There are many risks that would-be domain investors should carefully consider before buying and selling. The three largest risks are liquidity, subjectivity and legality, but there are also many other ranging from misleading appraisals to faulty escrow payments. Would-be buyers should carefully consider these risks before investing in domain names.
However, I'd argue that most people in the business really struggle as they don't understand what makes a good domain name and what's a bad domain name. While I do not work in this field full-time, I can say that I can make a living of it, but it's probably because I don't ask for absurd prices (e.g. domain name for $8000 is just unrealistic and won't happen) and therefore can sell domains easier. 
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.

Before EmpireFlippers became a website broker, the internet marketing duo Joe Magnotti and Justin Cooke had been sharing how they flip sites for cash on their widely-popular blog and podcasts. They relocated to the Philippines, hired locals to create content and build traffic, and then literally built hundreds of niche sites that earn from either AdSense ads or Amazon affiliate commissions. Every month, they chose low-earners and sold these ready-made sites on their marketplace.
It’s also not so easy to manually re-register. This is due to backorder providers which are paid to keep an eye on expiring domains over a certain period of time and then register them for the customer as soon as they become available. Promising expired domains are therefore usually sold before they have a chance to be put back on the registry menu for the public to look through.
To find popular phrases I opened up the Google Keyword Planner. This free tool by Google, allows you to find out how often a word or phrase is searched in Google. A phrase like “Yoga Mat’ has on average, about 10K – 100k monthly searches. That’s A LOT. However a more niche phrase like “Good Yoga Mats” only has 100 – 1K monthly searches. These seem similar, but I wanted to focus on the exact popular phrase that people are searching for.
Hi thanks a lot for this. I appreciate your honesty. A lot of people need to hear this. I needed this to. When buying and flipping domains always ask yourself who would actually buy this domain, what they can do with this domain and how would you monetize this domain if you bought it. Always think of your customer and treat it as a business. I think you’ll avoid a great deal of dissapointment down the line. Thank you
Many non-savvy internet users may not even be aware of the existence of other extensions. That said, because there are many new extensions popping up every now and then, you can often find amazing one word and 3-letter domain names with these new extensions that are otherwise almost impossible to find unregistered in the .com world. Additionally, these new extensions are becoming more and more familiar to users every day, hence it's almost certain that their value will continue to increase as time passes and wider adoption manifests.