Mature birds will sometimes hang out on their strutting area being spoiled as all the hens just come to them. One thing that works is to go to that area earlier than the Tom and call from there. Do not use a hen decoy as he will hang out expecting the hen to go to him. A jake decoy should work as he doesn't want any competition on his strutting area.

As mentioned already another tactic is to find where a lone Tom is going towards a bush and get there before he does and call from there. Be ready with different kinds of call as usually he expects a certain hen to be there, and if lucky you could just get the right pitch, just like the particular hen sounds.That's why sometimes certain call works and not the other.