@Imani Johnson, the easiest way I know is to show up in person. Almost every market has local investor meetups and REIA groups, and most of them run a Facebook group and post their meetings as Facebook events. Search Facebook for "St. Louis real estate investors" or "St. Louis REIA," join a few groups, and keep an eye on the events tab. Meetup.com is worth checking too.
Most of these meetings are free, or close to it, and they're full of people who are already doing deals in your city: landlords, flippers, wholesalers, lenders, contractors and agents who work with investors. Go to a few and keep going back. The first time you're just a new face. By the third or fourth time, people know you and you start getting real conversations, referrals and sometimes deals. Investors are usually happy to help someone who shows up consistently and asks good questions.
Here in Louisville I'm a member of our local group, KREE, and a lot of the relationships I rely on started at those meetings. I'd guess St. Louis has a few good options. Pick one or two and make them a habit.