When you're investing in a market there are only a few ways to legally protect your company from unethical (and if properly set up) illegal competition. Via the US government, you can apply for patents, trademarks and copyrights. That's it. As a word of caution any of these "protections" are only as strong as your willingness to pursue legal action against another person or company and to follow through. These aren't magic charms to ward away "the demons of competition". It takes effort and cash to establish these intellectual properties and cash to defend them.
Patents are the documentation and protection of inventions and proprietary processes. In short, it's complicated and expensive to apply and complete patent applications. Normally it takes years to finally secure the patents and you always run the risk of having your applications rejected as too broad, public domain or conflicting with prior filiings of others. For most small businesses, patents are impracticle to obtain because of expense, lack of experience and complexity. They are also very expensive to use as a "weapon" against others. A typical patent suit will run you low six figures in the courts to pursue to settlement. To pursue to trial costs a multiple more of that number.
Copyrights are easy to file. If you slap a "C" with a circle around it, name your company and the year you've created a basic and limited copyright notice to others. If you're serious about the copyright then you need to fill out and file your works with the US Library of Congress. If you file with the Library of Congress and someone violates your copyrights then you have much more substantial penalties if proven in court. These filings are easy and cheap. You mostly need to establish proper procedures within your company to create, file and record your filings. But unless you're a publishing company, record label or other media outlet they probably aren't very important protection for your business.
Trademarks are perhaps the most important filings you can make for a company. Trademarks protect the names and distinct images you use for your company and products as you sell into markets. If you don't have any trademarks then there is nothing to stop Acme Water opening up to compete head-to-head with Acme Liquids. Oh you can sue, but your claims will largely be baseless depending on what your state laws dictate. The same thing goes with your logos, product names, images of "mascots", etc. All of these items need to be legally filed and approved for trademarks by you in order to restrict others from using them.
So here are a few things to consider for trademarks:
Trademarks exist to protect consumers, NOT companies. Trademarks protect consumers from product confusion and deception within a specific market. You don't won't to buy Koka Cola thinking it's Coca Cola. If they are both cola drinks then Coca Cola is going to kick you out of the market. They'll start by sending you a cease and desist letter. It will get much more ugly from there.
You can file for national (US) trademarks through the US Patent and Trademarks Office. It's a few hundred dollars to file directly. You can also use an attorney but then you're paying additional hourly rates. Services can also do trademark searches for you. This usually costs around $400 and gives you a list of names, industries, websites, etc. that exist and could conflict with what you're looking to trademark. This will include state specific conflicts.
You'll want to make sure no one else is using your sought after trademark in advance and for your industry or "near" industry. There is no hard and fast rule but for example if you are seeking Blue Jewel Car Wash then an existing trademark for Blue Jewel Auto Repair may be too similar in services and industry to be allowed. Also be careful of preexisting state businesses. So for example, let's say you apply for a national trademark and receive one for Blue Jewel Car Wash. If a company already exists in Florida called Blue Jewel Car Cleaning and registered their company name with the state of Florida prior to your receiving the trademark then you're out of luck getting them to change their name. They were in the market place and using the name prior to your trademark.
So even if you have the national trademark companies using it prior to the date of your claim are free and clear of your trademark in the state they're registered. Now the Florida based company can't expand to Texas without running into your national Blue Jewel Car Wash trademark. But they can open several new locations in Florida.
Before you file for a trademark you need to use it in the marketplace. This is pretty losely defined but you need to put an ad in a paper, distribute some simple brochures to potential customers, etc. It needs to have the name and/or image you want to use. You need to note the date you took this first action. This is the first use date. This is important to your filing.
You can do a simple search of the USPTO database in real-time. This is not a definitive database (since applications that are new aren't in there) but it let's you look for any obvious conflicts. Very common words really aren't able to be trademarked. So for example, "Green Grass Seeds" is too general and descriptive for a grass seed product. "Jumping Rope" is too descriptive for a jump rope product, etc. You can always try to file but it's probably just a waste of time and money.
Sometimes the best thing to do is to create a "new word". Jumping Rope may be too descriptive for a jump rope product but "jumity rope" may be just fine to trademark. You also want to see what domain names are open and exist. It may be that "jumity rope" can be trademarked but www.jumityrope.com is already taken by someone. The domain name is preexisting so you can't "take it away" because of your trademark later.
If someone owns a trademark you can seek to purchase it outright or to license it for use. This is a one-to-one negotiation. The trademark holder's name and address is listed in the USPTO filings. They aren't required to respond to your inquiry so you may need to be persistent in your inquiries.
Protecting your business can be important. Make sure you look into trademarks. They can be the most effective to