If you mean varsity, and under the current "system," unless you are lucky, you would need to wait until there was an opening -- that would mean someone has died or retired or moved on to a "better" assignment. Then you would have to have made friends with somebody...either an official who has some influence over the assignor or, even better, the assignor himself. If you are a teacher or an ex-coach you've got an inside track. But even then, the politics of the situation might mean somebody might be better, or longer, friends so you'll still have to wait. You need to develop alliances and know who can help you along. But if you step on any toes you might not get a chance in any event, or might get booted.

If you mean JV, I think there are probably some opportunities, but it is difficult to improve your skills at this level because the quality of the wrestling. It's much easier to officiate good wrestlers. They finish their moves, don't do dumb things, and the coaches are stronger on their understanding of the rules. The pay is also a much less for JV work. A varsity tournament will pay $225+ and a JV tournament with more wrestlers will pay $150, and often you don't have an "extra" official to give you a break.