Instead of focusing on one domain name to sell quickly, try selling large volumes of domain names over longer periods of time. While this may require a more substantial investment, it will also return a greater profit in the long term. Remember, if you follow the basic principles of domain name speculation, there is good chance that your domain names will sell eventually.
Perspective buyers are able to directly contact domain holders in cases where the desired domain is no longer available. Most registries openly publish the names and contact data of domain holders. Once this information is gained, buyers can get in touch with domain holders and make an offer for the name. Sales are also known to occur in instances where the original domain owner had no prior commercial ambitions
Here's a test I have in process. I bought an old $5 closeout domain from Godaddy TDname expired auction. I put a quick minisite up and linked to it with a crazy anchor text phrase. The domain is ranking for that crazy term now. It's gone through one pagerank update and I'm waiting for a second to come. Then I'll redirect the domain to another minisite. I suspect the second site won't rank for the anhor text, but we'll see.
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.
So how do you develop that instinct? NameBio maintains a database of over 500,000 historical domain sales (as of writing this post). They have interesting filtering features by which you can narrow down domains by price range, date sold, keywords and more. Simply sifting through the listings on NameBio long enough will quickly develop your domain appraisal “instinct”.