Marketing

So…marketing. I keep hearing “social media, social media, social media.” I have been doing okay building engagement and likes and whatnot, but how do I get a “like” on Facebook to translate to feet actually coming through the door? What should I be building into my posts to create incentive to come shop?
I am wondering about how to identify our target market/customer. In the past, our customer has been majority women age 40-60, but we are bringing in younger styles and more trendy pieces trying to capture a younger demographic. (We are in a college town.) I am afraid of alienating our older customers. Any advice? Do we need to choose one over the other?
If you have a business and/or marketing plan, what sources of data did you use? Canadian sources in particular if possible.
In Store Events and other ways to promote a new business or reinvigorate a long standing one?
How to track marketing/advertising dollars spent?