In the weeks leading up to the Performance - Help them make time and space to practice every day. I recommend a minimum of 15 minutes, but any practice is better than none. Ask to hear their pieces, and to share what they have been struggling with and how they have been solving their challenges.
Before the Performance - Support the performer logistically. Are they fed? Do they have all materials ready and in good working order (including concert clothes)?
During the Performance - Polite applause is expected between songs. Use discretion when taking photographs; flashes can be distracting to performers and fellow audience members. We will be using a professional video camera to record the performance, and I would be happy to share the video with you. If you would like to record yourself, consider coming early and setting up in a discrete location where your camera will not be a distraction to others. Educate young audience members on what they should be listening for and how they should behave during a performance. Turn your phone off and put it away during the performance, unless you are using your phone to access the program. I have experienced students get downhearted when trying to make eye contact with a family member who is glued to the phone. This sends a signal that their hard work is not adequately valued. Make eye contact, smile, and show the performer you are proud of their hard work.
After the Performance - The performers have a lot of responsibilities to attend to before, during, and after the concert. Give them praise for their hard work and achievements, then ask if they need help with their post-concert duties. Presenting a performer with flowers is a traditional sign of respect and honor. Treating the performer to a trip to ice cream after the show is a great way to honor their work as well, and provides an opportunity for them to talk about their experience.