Do's Do have a well-defined mission and the support of your administration. Do find partners and collaborators for assistance and support. This kind of work can be frustrating and it is important to have people with whom to share successes and commiserate.
Small efforts can have large impacts.
Do work directly with the K-12 students on occasion. They are the reason this work is done and it is important to make a connection with them. Do be patient. School bureaucracies can be every bit as glacial as those of colleges and universities. Start with efforts that lead to small successes.