Torey Maerz and Carl Maerz, founders of Rocket Referrals, a startup company working out of StartupCity Des Moines, will hold a free lunch-and-learn to provide everyday tips a business can use to increase its referrals. The event will start at noon on Sept. 25, and take place at StartupCity Des Moines, 317 Sixth Ave., fifth floor. Rocket Referrals is a company that helps businesses follow up with customers and identify the ones most likely to give a referral. To sign up for the event, click here.