Cyrus pretty much covered it. I use my voice as well and have made my own birch bark call that I will use when I need more amplitude to the call. I actually use a bull grunt more than cow calling but use both. I carry a shoulder blade or shed to rake trees, branchs and it works very well. If you can' t find either you can cut out a silhouttte out of 1/2" plywood of a rack (one side) and this works to rake and hold up if you have a bull hung up, it may give him a visual and may help him to commit. One other thing I have used when calling near water is a coffee can, I pour water out to simulate a bull urinating, just an extension to calling by water. Moose like to travel on ridges and long skinning meadows are a great place to call in, water is always a good bet too. I would suggest getting some videos and than practice calling techniques as much as possible. (I find them easier than Elk to mimic and have found they come if in the right mood to even off sounding calls)

Rut here is as Cyrus stated, weather plays a big role in how effective calling or stage of rut will be. If it is hot and windy, you can pretty much forget calling. Get some cool nights or days and especially frost with minimal wind and you know it will be good. Now this may not totally apply to your hunt, but I bet it holds the same truth: cooler and calmer the weather the better chance to call in a moose. Have fun and hold on to your heart they are big animals and can make the hair stand straight up when they appear, respond, etc. Don' t be fooled by their appearance as clumbsy, they can motor through the thickest of timber and be very quiet. Some come in loud and hard, while others just stealth their way in with only a few hints they are near...have fun and good luck!!!!