skeeter 7MM has given a very good explination on techniques for rattleing. The only thing I could add would be; if you hunt with a friend, have one of you go down wind and rattle while the other gets at a cross wind from the rattler. A lot of times the deer will hear the rattleing and will almost always approch with the wind in his face. The person at the cross wind will get a couple of good shoots.

Lifes a garden, dig it.