Shoot the one that looks big. OK, so that's only half silly. Before going hunting, look at a lot of bucks (magazines, books, taxidermy shops, videos & TV, while scouting if you can) & get a feel for what makes up a handsome animal. Scouting gives you a feel for the representative size of buck to expect in your area. There's lots of "tricks" like comparing horn lengh to ear length (2 x ear length = 14 "), Prongs starting above the ears, etc. but for a quick assessment look for overall mass, height of & length of prong, total length & most importantly one that looks good to you. If facing me, I like to imagine his face (nose to ears) inside his horns. If it looks like there's not much room for his head in the horns save him for the last day. If it looks like theres plenty of room to spare start thinking about trigger control. Small bucks are obvious. Nice bucks are REAL hard to evaluate & the big boys? You'll know it when you see him. Antelope are arguably the prettiest critter out there and any buck pushing 14 or more inches will make a beautiful mount to be proud of.
When calling coyotes, more often than not they will circle on a target they are
coming into and approach from the downwind side. Presumably they do this in
order to align what they smell, with what they are hearing.
This means that you should always have your downwind side camouflaged and have
an open shooting lane. If the area is heavily covered the coyote could come in
take a look and be gone, with you none the wiser.