When the USPTO evaluates your mark to decide whether they will allow it to be registered, they look at how distinctive it is. They will not allow marks that are considered “Generic” or “Merely Descriptive” to be registered. See our previous post on Generic and Merely Descriptive marks.
The best marks are “arbitrary” or “fanciful” marks.
An arbitrary mark is a word that is arbitrary with regards to the goods or services it refers to. A famous example is Apple for computers. Apples have nothing to do with computers. Which is why their mark is so strong- no competitor has any good reason to use the word apple to describe their computer products and so Apple has a complete monopoly on that word in their industry.
A fanciful mark is one that is made up, or partially made up. Google is an example- it derives from the word googol, meaning an extremely large number. If they had named the company “Googol” it might have been considered suggestive of the number of search results one gets when one uses it. Another famous example is Kodak- it’s a made up word. Again, that’s great because it avoids being rejected for being generic or merely descriptive and it also means that no competitor will need to use the word.
There’s also a category called “suggestive” marks. These will be accepted by the USPTO for registration but it can be a thin line between suggestive and descriptive marks. A suggestive mark is basically descriptive but requires an additional mental leap that a “merely descriptive” mark would not. For example, “Jaguar” for cars suggests the speed and elegance of the car, but a jaguar is an animal and so there’s an additional mental leap required to understand how it applies to cars.
The best thing you can do when choosing a mark is to get creative and stay away from obvious terms that describe what you do or are used commonly in your industry. Another crucial step is making sure no one else in the industry has trademarked something that would be considered likely to be confused with your name. This requires a legal analysis, so don't forget to consult a trademark attorney.