Dr. Carl Pickhardt, psychologist and author of the article “Adolescence and Self-Confidence,” published on Psychology Today.com, says it's common for adolescents to feel less confident during early adolescence (ages 9-13) and at the end of adolescence (ages 18-23) as they leave home and enter the “trial independence” period. This lack of confidence can be attributed in part to changing schools -- entering junior high, high school or college -- and trying to adjust to functioning more independently in unfamiliar environments.

Think Positive Thoughts

While being confident at school comes naturally to some, for others confidence can be developed. Even the most confident person doubts himself sometimes. The difference is that a confident person refocuses and moves on. There may be a voice in your head saying, “I'm not smart enough for school” or “There's no way I can pass this class.” Ignore it. Instead, remind yourself of the positives -- you've made in this far, and you can accomplish much if you put your mind to it. According to TeensHealth, a division of the Nemours Center for Children's Health Media, listening to a negative inner voice can harm a person's self-esteem significantly over time. If you get used to listening to that voice, you might not even notice you're putting yourself down all the time.

Be Dedicated to School

Having confidence about school is hard when you're missing key pieces of information, say Lynn Jacobs and Jeremy Hyman, U.S. News & World Report Professors' Guide writers. In the article “15 Ways to Boost Your Confidence at College,” Jacobs and Hyman say attending class consistently is key to having confidence in school. When you only go to class infrequently, it's difficult to understand and follow the material. Skipping classes can also cause problems on tests. In order to be confident at school, it's important to keep up with classwork, study hard and take your education seriously.

Ask Questions When You Need To

Many people believe asking questions is a sign of stupidity. According to Vivian Ta, experimental psychology doctoral candidate at the University of Texas and Ms. Career Girl contributor, there are many reasons you might not want to ask questions at school, including insecurity, fear of annoying your teacher or simply not wanting to run the risk of sounding stupid. However, it's much better to ask questions sooner rather than later or not at all. In U.S. News & World Report, Jacobs and Hyman suggest getting feedback early. If you're reluctant to ask questions or address concerns in front of the class, talk to your teacher or professor privately. Consult with your teacher about concepts you're having trouble understanding, get tips on how to prepare for tests or present initial ideas for a project or research assignment. Keeping lines of communication with your teachers open will help you feel more confident about school overall.

Set Goals and Reward Accomplishments

Being confident at school isn't something that happens overnight. When trying to develop confidence, start small and work up to bigger things. For example, if you're nervous about speaking in class, set a goal of raising your hand to answer one question one week, two questions the next week and so on. In the article “How Can I Improve My Self-Esteem,” experts at TeensHealth suggest thinking about what you'd like to accomplish and making a plan for how to do it. Keeping track of your progress helps you stay motivated to achieve your goals. Once you achieve them, reward yourself, even if it's something small. Positive reinforcement makes it easier to keep working toward goals, say Jacobs and Hyman.