I OWNED DOMPERIGNON.ORG, incredible, but true.  Lost it, back in the days when internet in India was not a readily accessible utility. And I was a casual domainer.  You had to go to a cybercafe. Did that late in the day, towards the expiry of the domain. No chance of renewal. The domain is now with the owners of Dom Perignon and is redirected to domperignon.com! 
Check backlink profile: If you’re not familiar with what backlinks are, they’re basically any public website that “links” to the domain in question. Since there are numerous shady tactics in the SEO world, expired domains’ backlink profiles should be examined carefully. Check if too many links are coming from the same domain or if links have weird anchor texts/use foreign languages. You can use a tool such as ahrefs for these purposes.
If you’re patient enough, you can discover at least four to five very good .COM domain names at attractive prices. However, you’ll need to carry out some research and find out the right places where they may be available. I’ve seen that such .COM deals can also be bagged from popular domain marketplaces like Flippa.com, or from the private portfolio portals of sellers, provided you employ the right strategies. You can contact the domain owners directly too. There’s no harm in emailing them directly to negotiate the prices.
While getting a new domain name will give your site a clean slate and allow you to start a fresh marketing campaign, you may not be aware of the fact that some expired domains come with a high Page Rank value. A company that buys such a domain will not have to work so hard on website promotion and backlink building techniques. Thanks for updating this really informative post!
In addition to the quantity of incoming links, the quality of them also needs to be accessed. The main issues here are: where does the link come from? What kind of link is it? A high quality backlink profile is usually made up of different link types such as footer and sidebar links, links in comments, forum threads, and social media posts, as well as content links that come from other similar websites. It’s necessary to find out whether these links are marked as follow or nofollow.

Unfortunately, you probably won't like my tips. You need to look for quality domains at a good price and be willing to hold on to them to get your money back or know when you've invested wrong and get rid of them. Quality is in the eye of the holder, and believe me, I've looked at plenty of domain portfolios that the owner just knew were million dollar domains but in my opinion, they'd be hard pressed to get anyone to take them off their hands for just the registration costs. You have to figure that most of the best .com domains were registered in the 90's, and those are the ones you typically see the 6-7+ figure sale prices on. I'm not saying there isn't money to be made because there is. But it does take time, research and money, and maybe in some cases a little bit of luck. If you're thinking of getting into the industry, I recommend digging into the resources provided by Michael Cyger on http://domainsherpa.com and from there, moving to some of the other big blogs such as TheDomains.com or
There is NO accurate way to predict the sale of digital assets – if someone wants it, they’ll buy it. For example, those wasting their money on useless .com’s (LLLL’s that have no rhyme or reason) will spend 3x more time and money optimizing their useless name as someone that buys ANY keyword loaded domain (regardless if a TLD or new one). But these individuals who are spending thousands on domains will eventually get stuck with these domains in favor of (you guessed it) the oft forgotten yet highly useful 1-3 keyword domains. Why? Study Google’s algorithm as I have for over a decade, and you’ll figure it out.

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. 
In theory, you could technically acquire a domain for $10,000 and be able to sell it for $100,000. You could also acquire a domain for $10 and be able to sell it for $100,000, $10,000… or $100, you get the picture. Because of this, it’s hard to recommend a perfect starting budget because your strategy, experience, and the pace at which you learn will hugely affect your buying and selling decisions.