Forfeitures and jail time. Fines, I believe are ineffective for a lot of poachers, unless the fine is really high. Loss of hunting privileges should be automatic but hardcore poachers will poach anyway, without being licensed.
Forfeiture of everything that is possibly used in the commission of the the crime, vehicles (boats, airplanes, ATV's, trucks) guns, spotlights, etc go a long way. Jail time too. As much as possible for the level of the crime. And as much press time as possible.
I also personally believe that it is important that we, as law abiding sportsmen, actively observe, document and report any and all poaching that we witness. And follow-up on the subsequent prosecution and hold our prosecutors and judges accountable for anything less than near maximum sentencing.
We are sportsmen, hunters and conservationists...poachers are not on our team.