Key to taking decent phone photos is usually good lighting - if you can get your lighting down, you can get some good photos out of your device. Usually want to avoid dark areas. Also keep in mind that you can usually re-adjust the exposure by tapping on the screen where you want the camera to readjust (helps when a photos being blown out).
Try exploring with perspective a little too - phones are versatile and small, might want to try getting extremely low on the ground or hang somewhere high!
I haven't used a camera app in a while but I was using "Manual Camera" back in the day. It allowed me to use full manual control to get the photo I wanted.