Who, what, when, where.
A photo or graphic that shows some of the excitement of your game will help catch the eye, plain bold font (Times New Roman/ Serif type font/ 12 or 14 pt.) big enough be read from five foot (be short and concise) as the future gamer walks by in the hallway, tear off numbers at the bottom of the page with a contact name and number puts your info into the hands of the people who self select themselves for your game.
You could go on WotC site or any RPG site with a graphic and just copy/paste a simple, bold and exciting image to use that will catch a muns eye and dwell in their mind long enough to come back and snag the number at the bottom and then call you. Don't worry so much about copyright infringement with the image, you are only using it for the start up of your game and unless you expect to charge for attending the game you will not be using it to profit. I took a macro photo of a mini I painted and used that, but I am sure if it was a Games Workshop mini I could expect a letter of cease and desist form their lawyers, same goes for WotC if they ever find out you used their image. Besides either of those two, you could e-mail the site owner and ask for permission and get a more permanent relationship.