Temporary exhibitions are a good opportunity to attract young people. Perhaps a fashion show could provide a chance to try the clothes on. The buildings of many museums might possibly be used for many other things. This would bring people into the museum. Links with schools and colleges could bring more young people into the museum.
Most museums have lots of work-placement opportunities.
Also jobs such as ushering at special events could be done by young people. This sort of thing would raise the awareness of young people about the museum and make it part of their normal lives.