The .com or co.uk/.uk is free to register
If you’re trying to sell a .co.uk and the ,com version of the domain is free to register, then you’re going to have a bad time. Most business owners will automatically pick the .com over .co.uk/uk and you will really struggle to sell it for above market rate.
My Advice: Register the .com/.co.uk/.uk as well and try to flip as a package.
A domain packed with a few juicy keywords may look attractive, but it’s niche appeal will make it difficult to flip. There’s not that many specialist light blue tent sellers that are looking for a domain name.
My Advice: The more niche you go, the smaller your potential market for the domain.
Domains with a trademark
Nobody is going to want to buy a domain with an existing trademark in. It may rank highly for keyword scoring and google search volume, but it’s potential for profit is zero. If anything you could find yourself in legal shenanigans or in a dispute.
My Advice: Avoid, unless you’re mates with a lawyer.
Hyphens are a good way of registering a brand or keyword based domain if someone has already bagged the non-hyphenated version. Nobody is seriously going to pay £1000+ for a hyphenated domain. No matter how relevant or how many keywords it contains.
My Advice: You’re selling a premium domain name. A premium domain name doesn’t have hyphens in. Avoid.
The value of the domain is based primarily on it’s earning potential. If there’s no demand for the product or service online, then there will be very little demand for the domain. If a product is illegal or can’t be purchased online then you will struggle e.g cigarettes or pornography. Also, if a product is primarily purchased in-person.
My Advice: Research the market before you buy a domain and use a bit of common sense.
If you have any more advice on what names to avoid please leave them in the comments.