Yes, you have received some excellent advice. The
two things I would add are, you might go out with
bino's some morning and sit at a distance and see
where the birds fly down into the field or walk into
the field before deciding a spot to set up. There is
nothing better than setting up where they want to be.
Second be careful about how much you walk around
near the roost site as roosting time approaches, that's
the time to be sitting or standing still and just listening.

Good Luck