If it's a buck either a challenge grunt or a tending grunt usually will draw them in. Some times I'll do both. "I'm after this hot doe. Hey you SOB, stay away from my woman."
Tending, uhh uhh uhh uhh uhh uhh
Challenge, buwaaaaaaaaaaa uhh
If it's a doe or a fawn (does grunt just as low as a buck) an occassional buwaa just to let them know you are there.
When you are sitting around seeing nothing blow it short every few minutes for a bit every half hour. It gets boring blowing it all day long, try to time it so any deer that may have had time to walk in will hear it.
I had a tree creaking once that I think called in a little doe. It was creaking the whole time I was there. She came in looking for something and bleating.
Once while searching for a downed doe I heard, trot trot trot, buwaa, trot trot trot, buwaa, trot trot trot, buwaa. That all this buck did the whole time he was in my view.
If you're prepared to hunt from the ground blow it while you're walking to your stand. But this can catch you with your pants down. They can come in pretty fast when you add crunching leaves to the call.
If they are ignoring you they may not be hearing it. I start soft and blow it louder until I get some response. They may look up and continue to walk off but I've never had one spook at a call.
When they are close and you're trying to get them in closer, bend the tube around to throw the voice behind you. When they are far aim it right at them.
Also use your hand on the end to give it a mouth, like with a duck/goose call. Slowly open and close so it sounds like it's coming from a mouth.
I also like voice calling but it's hard for me to get a grunt to come out loud enough.