As the title suggests, get your clantag out there. Find a surface that you can write on, preferably in a public place (but which can be cleaned - for example a whiteboard, chalkboard or simply a dusty surface - be creative!) and write your clan tag on it. Post an image of it here and include a description of where it is. Have fun! :)
I'll kick this off:
http://imgur.com/HX5eS
This is on a dusty TV backstage at the Sydney Opera House, Australia. The SPQR clan will be immortalised on that TV until it's next cleaned :P