Enter the email newsletter. "Oh, but I don't want to spam my customers!" you think to yourself. Or perhaps you haven't been keeping track of people's emails, which in all honesty, you shouldn't be doing without their owner's permission anyway. Enter Mail Chimp (or another contact/email system), a trusty spiral bound journal of sorts, and a healthy sense of propriety.
I like them because they're free, super easy to use, they have a monkey as their logo, and it says funny things to you. I'm on their Forever Free plan:
Ok, so you've gathered and organized your email lists. Now to determine what to share, and when to share it.
Alrighty, I'm sure that's enough to get you started.
Good luck, and a happy Tuesday to you!