Some of the best stories have an element of truth to them. Even though I write fantasy novels, my characters and the situations they find themselves in are usually based around things that have happened to people that I change and exaggerate beyond recognition. So, for this practice exercise, recall an incident that happened to you or to someone that you know. Write it down as it happened, fact for fact. Don't change anything and don't get creative. Just the facts.
Now, take that incident and turn it into fiction. Change and embellish until you have a story that captures your readers. At the moment, your reader might only be you, and that's okay. Create a story that you enjoy reading based upon factual events. Your finished story might look nothing like the factual account, and that's fine. The point is to find inspiration in real life and change it into something people might like to read. That's the point of being a writer, really. To have someone read the stories you've written.
You can repeat this exercise as many times as you need to. You might find that certain events lend themselves to becoming fiction and others are better off as non-fiction. This is normal. Experiment and see what works.