There is only one hard and fast rule for using the TM, SM or ® symbols-DO NOT USE THE SUPERSCRIPTED ENCIRCLED R (®) UNLESS YOU HAVE A VALID REGISTRATION FROM THE US TRADEMARK OFFICE. The superscripted TM and SM may be used to indicate that the user is using the mark in a trademark sense, regardless of whether or not an application to register the mark with the USPTO has been made.  Actually, there is another hard and fast rule for using your trademark: always use it as an adjective to qualify the product (noun), never as a noun.  Back to how to use the TM, SM or ® symbols, as applicable, please note that there is some flexibility in placement.  That is, while each of the respective symbols are typically placed in the upper right-hand corner of the word mark, word mark & design or logo (i.e., superscripted), the symbols alternatively may be placed level with the mark or logo itself—each is an acceptable way of displaying the appropriate symbol. Example: COCA-COLA®. The TM, SM or ® symbol need only appear with the first or most prominent mention of a mark in all documentation, such as press releases, articles, and company reports.

Reference: International Trademark Association