Determine whether your slogan may qualify as a trademark. Because it is difficult to tell what has a good chance of being accepted as a registered trademark, you should examine the United States Patent and Trademark Office (USTPO) guidelines or speak with an intellectual property attorney about your slogan.
Search the USPTO's Trademark Electronic Search System to make sure that your slogan does not conflict with a preexisting registered trademark. If you believe a conflict exists, check the status of the trademark with the Trademark Applications and Registrations Retrieval (TARR) database. Write down the serial or registration number of the conflicting mark to access information on the TARR database.
Draft a description of the goods/service associated with your slogan. Applications that do not specifically identify the good/service connected to your slogan will be considered incomplete. If you have questions about how specific your identification needs to be, consult the USPTO's "Acceptable Identification of Goods and Services" (see resources below).
Include in your application a representation of the mark you want to use. Because a slogan consists of words only, you must use a standard character format, which means that you are not making a claim to any particular font size, style or color.
File your trademark online with the Trademark Electronic Application System. You can file by mail, but hard copies take longer to process and costs more. The filing process costs $275-$325.
Wait for a summary of your filing. If you file online, expect to receive by email an immediate summary of your filing and a serial number for your application. If you file by mail, your receipt of filing and serial number should arrive in 2-3 weeks.
Wait to receive a response to your application from the USTPO. Responses usually arrive 5-6 months from the date of application. However the USPTO warns that the total processing time can take anywhere from a year to several years, depending on legal issues that might arise during the examination of your application. You can check on the status of your application on the TARR database.