The following is guidance only! I'm not a lawyer so if in doubt contact one!
I was asked whether there were any rules on how to apply the TM sign on logos and icons to protect them. I have done this some time ago for companies but needed to refresh my memory so here is what I've found out: You can apply the TM sign on any of your trademarks at any time to claim rights in it. The C-Circle can be applied only once the mark has been registered. (Ref 1) (Ref 2)
If you are concerned about this ruining the layout of your brochure as you have to dot the TM symbol throughout then fear not fellow creative as you can add it to the first mention in the text or the most prominent usage of it. (Ref 3) "When in doubt, err on the side of “over-marking.” "
And what about your beautiful logo that you've designed? Will it be ruined? Well all I could find is this mention:
"Remember that apart from marking, a trademark should also be properly used (e.g., used as an adjective and distinguished from surrounding text by capitalization, distinct typeface, color and/or size)." (Ref 4)
"These symbols are often put in superscript (smaller, raised) form." (Ref 5)