First thing is to locate them. Use a crow call or similar type call early in the morning to try to get a response. If no response use a hen call. If no response use a Gobble.
You may have to do this often. Sometimes they won't call back so keep your eyes peeled always looking. It's nice to be there the night before and "put them to bed". Call when they are going to roost or on their roost so in the morning you can slip in, get your decoys "quietly" stealthily set up. Get back a bit and call when it gets light. Don't try to call them "across" a river or even a fence, they usually will not come, fence maybe but river or water almost never. Shoot them and eat them up.