Develop strong sides
Many of the properties that present a problem with ADHD are also good qualities in many situations.
Impulsivity can imply joy of discovery and creativity. Hyperactivity can imply endurance during physical activities and great opportunities to have time for many things. The difficulty of maintaining concentration when it comes to boring tasks can lead to the adolescent finding exciting and challenging activities. Spontaneity can often be an asset.
It is quite common for adolescents with ADHD to have bad self-confidence. It is therefore important to take care of the strong sides you have. Embrace your interests and strong sides. Look for things you are interested in and good at and stick to those. Try to find ways past difficulties and minimize the risk of failure - both in terms of learning and social. Bring attention to your strong sides.