Federal Trademark Search
Locate the "Trademark Electronic Search System (TESS)" on the USPTO website by clicking "search marks" on the Trademarks Home page. This is the system in which you will search for federally registered trademarks and pending trademark applications.
Click on the "Basic Word Mark Search" feature of TESS. On the next page, type the name you want to search in the "Search Term:" box. By leaving all other queries in their default settings, your search results will include all similar names -- not just identical names -- currently registered or in the application process.
Review the results of your search of the USPTO records regarding the goods or services associated with each name in your results by clicking the link next to it in the "Check Status" column and scrolling down the subsequent page. This is to determine whether any of these names are used on goods or services for which you intend to use your name.
State Trademark Searches
Locate the website for the state agency that oversees trademark registration in the states where you intend to do business. This is typically the secretary of state.
Search the state's registered trademark database to determine if there is a state registered trademark similar to your name that was not registered with the USPTO. Some state agencies, like the Indiana Secretary of State, provide the information online Other state agencies, like the Connecticut Secretary of State, require that trademark search requests be submitted by mail.
Conduct an on-site review of the state agency's registered trademark records, if the state agency does not offer searches either online or by mail. Depending on your circumstances, this may require the use of a commercial trademark search service.