A couple "looks" generally catch me: "robust/sturdy," "dorky," and "striking."

Robust/sturdy: typically have a larger frame than other relatives of theirs, like larger antelope, orcas, draft horses, big cats, otters, red kangaroos, sharks, Rottweiler

Dorky: these are often humorously-proportioned, often tall and/or lanky: toucans, herons, giraffes, whitetail deer, coyotes, caribou

Striking: often this mixes with the others, and mostly pertains to patterning: zebras, giraffes, gemsbok, bongos, orcas, etc.

That said, I can find almost any species handsome if the artist captures unique elements of that species's look in anthro form. An anthro zebra with tiger stripes doesn't grab me, nor a horse with lizard nostrils, nor a coyote with a wolf snout. Study your references and make your creatures appealing for what they are!