Like the rest of the guys say there is no exact science to calling/grunting. You are basically trying to sound like deer....pretty simple. I blind call more that most about every 10 minutes, but I never blind grunt. I use a doe bleat or fawn call when blind calling and it works for me. My area is very thick, visibility is poor and the deer seem to call more in this environment. On calm days I can hear deer talking on most hunts. When you are calling to an animal you can see that's when your judgement comes into play.....use your best judgement and build on your experience. My favorite scenerio is a doe and fawn talking to each other..... I called in a nice 8 point this Sunday with that one. I have better luck with the doe bleat than with the buck grunt and use that call the most. I use the Away Bowgrunter Plus as my main call and it works well especially with a full face mask and I back that up with the True Talker and a Lil Can. I have had deer not respond to my main call and come running to on of my backups. IMO calling deer really works...good luck