as other stated,
lots of info out there,
and just working a field is too vague to offer much advise,
as most hunting learn the birds patterns,
when and where they go,
will definetely want to learn the calls,
can practice that anytime,
get a couple basic calls and practice any time,
mouth calls are common and leaves your hands free,
i find mouth calls a real pain and gag every time,
i prefer a slate and stick call,
what ever call you decide, learn to use it, and get reactions like the other poster,
i often carry a call with me even when just hiking in the woods,
also call them into my backyard in PA.
when actually hunting early morning is key, as they come off their roost very early,