A strong domain name is the key to your Internet presence. It should be recognizable and relate to your business name, brand, product, and/or activities. Make sure it fits on a business card and is easy to remember whether seen in print or mentioned over the phone.

Good extension - If a person is surfing around looking for a site, and they know its name, most people will try .com. So, for the web site owner who wants their site to be found, the rule is: if at all possible, get a .com domain.

keeping them short : A domain name is as short as possible. That makes it easy to remember. As a rule, a good domain name has under 15 characters. That's should be enough for two or three words.

Easy to spell - Make sure it passes the phone test, also be careful about double letters.

Trademark - Ensure that there will be no trademark or other legal problems with the domain name you choose.

Country Domains - If you're marketing your products and services primarily to users in a single country then seriously consider using that country's top-level domain.

If possible, do not use hyphens.
If possible, do not use numerical characters.

Cover your options and buy more than one domain if you need to.

Choose the right domain provider. They are not all the same and many have hidden charges.

Try to buy a .com name - the best search engine results come from dot coms. And most people assume you are a dot com website if you tell them.

And finally, check your spelling before you buy and register online.