In this day and age it's not uncommon to have one or two side jobs in the evenings. Maybe you're clearing out the clutter with FB marketplace, drawing comics for IG and selling books or stickers, promoting your bands' next show or running an online shop that sells your hand made stuff. Like it or not, having a couple jobs is the new norm. Making that second job worthwhile is a tricky endeavor though... It really helps to have a group of peers to lean on, to learn what worked and what didn't, so you can fine tune things.
Case in point: this short article from a designer on how to use conditional logic, visual consistency and little bit of design to improve trust between you and your audience. It's a real-world case study from an advertising perspective, so don't let that scare you. It makes the points, backs them up with numbers and gives you a couple insights you probably never even considered. Think of it as a mini TED talk of the day and I think you'll find it enlightening.
Using design to fine tune your business is sort of like this gent I photographed in Taipei during Computex, he's taking a personalized approach to no-parking outside his apartment building.