When you were young, picking the perfect IM name was as simple as slapping your birth year and several “x’s” together and calling it a day. A domain name is little more sophisticated than that. 
To provide some guidance on the decision, Moz’s Rand Fishkin provides expert advice to avoid choosing poorly.
Think About Your Brand
One of the first things Fishkin mentions is branding. When you begin a website, branding may be far from your mind. This is the most crucial consideration to a domain name. Unfortunately, the name game is a bit touchy. As Fishkin mentions, domain names should steer clear of hyphens, extra periods, and numbers. Under this theory, the site 9gag.com would not work; however, the site’s content proves to be profitable.
Generally speaking, numbers and hyphens come across more like a teenager’s blog than a professional website, but they have their uses. Your main focus should always be the brand. Even if you do not expect to make a profit off your website, a poor domain name will not bring visibility to the site.
Make It Easy On the Eyes
It’s easy to think of a unique name. As children, we came up with silly names for things all the time. As adults, you want to take that same creativity and make it into a marketable brand.
One of the tricks to marketability is making things look appealing. This may seem like trickery, but it’s similar to photographers that take photos of fast food. The pictures never look like the food handed to you through your car window. In order to sell the food, the pictures need to be easy on the eyes.
A domain name is the same. If the domain name is a long sentence that requires viewers take it apart to read, you are probably in dangerous territory. Remember – you want to sell the food using the most appealing picture to new visitors. Keep your visitors’ eyes in mind when making a domain name.
Have The Right Length
Keep it short, but not too short, says Fishkin. This means you should probably skip the domain names that never seem to end. Think about your audience. Typing a long domain name leads people to make mistakes. No one wants to type all that out, nor does anyone want to share the link. Linking is a crux to success, so keep length in mind.
As a general rule, the shorter the better. As a secondary caveat, avoid going too short. You still want the name to be easy on the eyes and good for marketing. As an example, Fishkin mentions a possible domain name of pastasci.com as a no-no. It is short, but it fails the easy on the eyes test. Pastascience.com is more marketable and easier to read, he says.
Stick With .com
Why .com? If the point is to be unique and stand out, why do you need to use a .com address? There are so many other options like .net to use. While creativity and uniqueness help a domain name to stand out, .com is the most recognizable.
When thinking about the branding of your domain name, you need to consider your audience. If a website is not .com, then users may feel that the site is untrustworthy. Fishkin does make the point that .net may make sense if a .com is already taken. Likewise, a .ca or .au may be more useful to your geographic location.
Stay Away From Other Brands
As we already discussed, domain names need to be unique for your branding. Branding is important, but unique names are important for other reasons as well. Domains and branding hold copyrights.
In the quest for success, you may think it’s a smart strategy to use a similar domain name as a popular website. If you aren’t careful, you could end up with a domain name that gets you sued. At best, the original brand may pay you a small nuisance fee if they think you are a problem. Either way, it is dangerous territory to be in if you want a successful brand.
Another reason that another brand might become upset is due to the confusion of their customers. If their customers constantly misspell the domain name, it may take them to your site. Your site, as a result, suffers from a high bounce back rate and potential legal claims.
Does It Make Sense?
Fishkin says it best when it comes to domain names: “Oh, I’m guessing they probably do this. This is probably what that company is up to.” You want the reader to be able to look at the domain name and instantly understand what your brand is all about.
For instance, a domain name with the word “flowers” in it might suggest a company that sells floral arrangements. If you run a food blog, a domain name with flowers in it may not make any sense to the consumer. A confusing domain name may become a fun joke later on if the brand becomes successful, but it weakens the possibility of success.
Consider Keywords With Care
Keywords are great for optimization, but they shouldn’t be a crutch, says Fishkin. Keywords may help boost your domain’s success, but it needs to make sense. Blindly slapping in keywords into a piece of content does nothing to boost success. The same goes for domain names.
If the keyword makes sense, then go for it. It will probably help, but you need to be careful. If the keyword is too branded, it won’t help to use the keyword, no matter how much it makes sense to your brand.
Sometimes Unique and Creative Works and Sometimes It Doesn’t
Sometimes, creativity leads to the 2000’s IM name. Other times, it makes sense. For instance, brick and mortar businesses in different states often share the same name. If another business has your domain name already, then adding to it is okay, say Fishkin.
Again, just make sure that what you add makes sense. Articles like ‘the’ or ‘a’ are probably okay, but you should steer clear of extra letters just for the sake of it.