Summarize this article:

When discussing your sport or academic subject, talk about how much you enjoy it. Tell your friends and family that you plan to do your best in an upcoming activity. Demonstrate your knowledge in an interested but not an arrogant way. People will notice your interest and might regard you as being good. They might ask you further questions, which is an opportunity for you to show your expertise. For example, you might say, "Wow, I'm so excited for my competition this weekend. I have been working really hard with my new choreographer and cannot wait to give my full effort." You also might discuss a recent news item and your thoughts on it. It is also okay to express doubt or worries sometimes. Instead of broadcasting your thoughts, however, tell only a few close friends or your parents. This will help your confident image stay. Whether you are taking an exam or performing a competition routine for figure skating, express confidence. Use confident body language when conversing with others. Smile at others. Do not slouch. Instead, stand up tall and speak clearly. Rather than crossing your arms, keep them open or at your hips. See Make People Think You Are Confident for more tips. People who are well-rounded might seem "good" at everything because they are well-connected. In truth, they might be generalists who just try many activities. Being open to new experiences, though, is in fact a good thing. Plus, the more people you meet, the farther your reputation spreads. Consider finding friends in different areas of your school or community too. For example, if you're into skating, you could have other skaters as friends. You might also have friends from chemistry class or choir. In addition to concrete activities, being "good" at everything, extends to your social skills. Show kindness through volunteer work or helping friends when they are in need. Listen intently when your friends tell you stories or about their problems. Give advice when they ask for it. Also, compliment others. Often, confidence comes from not having to prove your the best but in highlighting the best in others. You might consider volunteering at a soup kitchen or collecting food for the homeless. You could help your friend with her math homework. See Practice-Random-Acts-of-Kindness for more tips. No one is good at everything and absolutely no one is perfect. If you want to appear competent in what you do, that is good and fine. It is important, however, to be modest and humble. Do not brag about your successes. For example, do not say, "Wow, I went to the competition this weekend and beat everyone in the free skate. I won gold!" Instead, wait until people ask you how the competition went. Then you might say, "I did my best and was very pleased." If they ask you what place you received, then feel free to say, "I placed first." See Be Humble for more advice.
Speak confidently about your activities. Act confident. Socialize in many groups. Be kind to others. Maintain humility.