If someone uses a brand identical to yours a lot of things can happen.
First of all, they won't be happy if you are using a similar brand. Moreover, using a brand identical to a prior brand is illegal in many countries.
But how to find out if a brand is available?
When comparing one brand to another, you need to compare 2 things:
1. If the marks are similar
2. If the products/services the brands are used for are similar
The more similar are the marks, the less similar could be the products to decide that the brands can cause confusion.
You can check US trademarks in the official database of the USPTO: https://tess2.uspto.gov/
While it may seem easy, think that if you search Gogle, you won't find Google but - oh boy - Google won't like if you apply for Gogle. Trademarks are not like domains. They don't have to be identical to cause confusion, it's enough that they sound similar or look similar or have a similar meaning.
When you found the marks that might be conflicting. You now must check how similar the associated products and services are. And there is a catch. Coffee is similar to cafe services. Bags are similar to clothings. Retail services for cosmetics are similar to cosmetics. Etc.
The main objective is to find out in what class you services/products fall into and check the marks only in this class (you can check here). It won't be very accurate, but it will allow you to spot obvious conflicts.
Hey, and the best part is that you don't have to do it by yourself! You can request a free basic search from us anytime, free of charge: Free Search
If you want to go further, you can request our attorney's opinion, but that's optional.