You can run some highly-localized campaigns on social media networks that automatically target each locality your franchises are in.

Try online pay-per-click advertising on Google & Facebook if you have a budget, but beware that without the proper setup & management you could be throwing money into a hole.

Grow your email lists, segmenting for each franchise/location.

Find out where the population is growing in your area and send physical mailers out with a coupon that invites them to connect on social media or an incentive for a referral.

Hope we can find a time to talk strategy, I have helped several businesses who have never done online marketing to start hitting home runs!

Pete