*Animals have keen noses, so do people smoke when waiting for their targets?
I dont while yote hunting.
*Calibers can be too small to humanely use, but can a round be too big(say you are not going to keep the hide or whatever)?
Yes
*Would you recommend I get a digital caller for my first couple times, a reed caller or something else?
I would say just pracitce on reed calls
*Any tips you want to offer to help me be more successful?
Remember what Howler said about the down wind thing. always be looking downwind, and play the wind.

Good luck and have fun!