The first official step in registering a trademark is to file an application at the Trademark Office. If you want trademark protection outside the U-S, you have to file an application in every country where you want your mark to be protected. For worldwide protection, this can be an extremely expensive process and is generally used only by large corporations. Prior to registration, you should make sure that your proposed trademark is distinctive and available for use. Distinctive means that it can't be confused with existing trademarks or generic names. Finding out whether a proposed trademark is available for use involves an extensive search of existing trademarks. Since it's sometimes unclear whether one trademark will infringe on another, you should seek expert legal advice in this matter.