Anytime you have a chance is the best time to go. In Missouri your only allowed to hunt daylight hours the most productive time to me are the first and last few hours of daylight. Until the the temps really drop in winter then they will be up feeding more throughout the day. As far as calling I use a mixture of howl's and distress sounds and for the calls themselves the new e-callers are wonderful I hear if they are legal to use in your area. Closed reed calls are the easiest to use as far as a mouth blown call and open reed are the most versatile.
These Ozark Mountains Ain't High But The Hollers Sure Are Deep