1. Using Natural Light
This one is pretty simple and straight forward, but without a doubt, one that is often times overlooked. No matter where you are, if you have no light, and you are trying to shoot with a smart phone, the photo is not going to work. You will find yourself trying to take a good photo with a little bit of lighting and will struggle to bring out the colors etc. Use the sun instead, shoot during the day before night time. There are exceptions for example if the place is well lit or if you are doing product photos, but for the most part, it makes sense to take pictures in the day time.
2. Stabilize your Smart Phone Camera as much as possible
This one is challenging because the human hand is not very steady when trying to take pictures. Image stabilizers will work wonders but the best practice here is to at a minimum, use the headphones with your iphone to take the picture. When you use your finger on the image button inside the screen, you will create movement on the camera when you take the shot.
3. Use your own perspective
Taking a photo from different angles will really help you stand out from the norm. Use your creativity and step outside of what people usually do. When you take the same picture as someone else, you won't have anything else to show. If someone was selling apples and you were selling apples, offering to dip them in charamel would set you apart. Think different and offer a different point of view.
I hope these have helped. Learning isn't always the easiest. When you make mistakes though, you eliminate having to make them again.