when I started officiating, my coach put a paper up, sign here if you're intrested. Scince then I've helped recruiting something like 3-4 refs. All have been too my games, I've encoruged them to start, one was on the same training as me (wich was a joint between ref and coach) and should start coach. After 2 hours in my company, she was convinced to start officiating insted :P somebody your own age is also a much more presvasive person. If you want young refs, get younr people to inspire them
that's my tip