Art school can teach you many things. The most important lesson I learned is about mistakes. Art school taught me to be open to the idea of making mistakes. Do not be afraid of making mistakes. A mistake can turn out beautiful, if you let it. I throw away more sheets of paper than I use for final artworks.
During the artistic process, I can completely ruin an artwork. That is completely fine. Mistakes are going to happen. If you are too afraid of mistakes, you limit your creativity. Because if a new technique you try doesn't work, it just means you need to keep trying new ways until the technique does work.
Don't be afraid to try new mediums of art. I recently tried alcohol inks, and discovered I love them. I have also tried oil paints in the past, and have discovered that I am not a huge fan of painting with oils. I've also painted acrylic on wood and board. I've tried sculpting and pottery. Keep failing until you find the medium that speaks to you.