Whether you want to register a trademark that you have just created or a trademark that you have used for years, the first step in the trademark registration process is to determine whether and to what extent other parties are using trademarks similar to yours. A comprehensive trademark availability search will help answer two questions relating to your trademark: (1) "will anyone have rights superior to mine?"; and (2) "will use of my trademark subject me to liability for trademark infringement?"
The availability search should be performed by a competent trademark research company, and the report should be reviewed and analyzed by a competent trademark attorney.