I tell people that in trademark world, "it's not about you."
This is because trademarks are source indicators, meant to protect the consumer. This means the buyer is king, and folks with trademark rights are simply acting as guardians of a unique word.
Is your mind blown yet?
Now, because trademarks can only be used to protect unique identifiers of source, there are some types of words and phrases excluded from protection. This is due to the fact that they either 1) don't indicate source, or 2) can't reasonably be protected to indicate source without additional information attached. Your mark will get rejected if you try to register these types of words and phrases (unless you've got an attorney who can navigate the landmines, of course, and even then you might be out of luck). This is why it's uber important to keep these rules in mind before picking out a business name!
So you want the quick and dirty? You can't trademark:
1. Generic terms, like "cat," "wedding professional," or "event photographer."
2. Descriptive terms (without proof of the acquired distinctiveness of "secondary meaning," an actual legal standard that means "when-someone-hears-x-they-immediately-think-y").
The USPTO says: "A mark is considered merely descriptive if it describes an ingredient, quality, characteristic, function, feature, purpose, or use of the specified goods or services. See In re Gyulay, 820 F.2d 1216, 3 USPQ2d 1009 (Fed. Cir. 1987)." They give the examples of rejected marks "COASTER-CARDS" for coasters that can be mailed, or "BREADSPREAD" for jams and jellies.
3. Surnames, unless they have been used with a product for a long time and acquired secondary meaning (see above).
4. Geographic locations, although this has a lot of caveats (including this one for champagne/ Cava #CHEERSbabes!)
5. Anything misdescriptive or deceptive, which would include an indication the product is from a certain location ("DENMARK CHEESE" for a cheese produced in California) or a mark that's a twist on another famous mark (which actually might be trademark infringement, but I digress).
Keep these in mind when naming your business-- because "Wedding Planners of Michigan" isn't going to cut it!
Note: This post is meant for educational purposes only, and not meant to substitute for the counsel of a licensed attorney. Please contact an attorney in your locality, or contact my firm separately to engage us for federal matters (e.g. Trademark, copyright, CAN-SPAM, or federal employment regulations). Caroline is a lawyer, but she's not your lawyer. This post may contain affiliate links.