Well, it's pretty fun to practice during the moose pre-season scouting trips. Since scouting is the primary reason I'm there, sometimes it's hard to be patient and give the call a long enough time to do its magic! Maybe towards the end of the day, when you've found a moosey area.
Another good time to see how effective your calls are is when you see a moose. More often than not, even if they're starting to beat feet out of the area, they'll stop for a call and occasionally come back to investigate.
I was kind of embarrassed when I first started calling. Sort of sounded like goose farts on a muggy day, but I kept practicing and by and by got to where they consistantly sounded a lot more like the calls on my instructional tape. Guess the moral there is to keep practicing!
If you're lucky enough to be on private land and can leave your stand up during the off season you can tie an old piece of cloth or something of the sort to your stand. I like to use an old camo bandana that I have. That way the deer get used to the movement and eventually don't bother even looking up when there is slight movement. This may just give you the time to draw your bow or raise your gun without being detected.