Useful experience includes things you have actually done that reveal how you handle responsibilities, solve problems, learn, or work with people. It can come from paid employment, study, care, volunteering, household responsibilities, or personal projects.
Start with a specific episode rather than trying to label yourself. What needed doing? What did you do? What happened, and what remains unknown? Keeping those details separate helps you describe something real. An ordinary example becomes useful through clarity and relevance, not by turning it into a dramatic success story.