2. HAVE A HOOK
You need something unique to draw people out of their homes - where they're perfectly comfortable playing CoC - and get them to the location of your choice. What that "something special" is depends a lot on your resources, venue and culture. I used a two-part combo - the social hook and the freebie.
What is a social hook?
A social hook isn't directly related to the game. It has more to do with the setting and the people involved. For me, the answer was easy. Portland is a big beer town. Everyone likes to drink it and everyone likes to talk about it, meaning it's something most Portlanders have in common. Guardian Games has a bar in the back. Beer? Bar? Cards? Presto!
Focusing on beer had an added benefit - it downplayed the anxiety of gaming with strangers, as well as the geek-factor of playing at a hobby shop and the immaturity/social stigma that is often associated with those locales (I know they can make me feel uncomfortable). In turn, it emphasized the fun, lighthearted nature of our group. Plus it gave everyone a non-nerdy excuse to show up - drinkin' beer! Trust me, it's not for nothing that I'm calling my league nights "Mythos and Microbrews".
For your own social hook, you may consider playing in a venue that other Lovecraft fans will find attractive. Or catering to people who like beer, wine, a type of food, music, etc… You can also package CoC with another game that Mythos fans like to play - namely Arkham Horror - to create a Lovecraft-focused night/day at your game store. Another interesting idea is to hold a "Cthulhu Movie Night" paired with demos of the Call of Cthulhu LCG.
What is a freebie?
Another good hook is the giveaway. When it doesn't cost anything to play and you're giving away something a player wants, that becomes a strong enticement for people to show up. I don't have a big budget for games, so I needed something cheap. I found an online site blowing out old CCG-era starter sets at firesale prices. I then used the duplicate cards - notably the domains and story cards - as my giveaways.
For your own freebie, you could do the same with this:
Artscow is constantly running coupons with either free shipping, 20% off, or free shipping + 20% off. I've picked up a few of these packs for $9.99 or less, shipped. With 18 sets of unique domain cards, they make a great giveaway for such a small investment.