Usually people who don’t appreciate have a slew of other problems. So keep your eyes open for signs of an attitude problem, arrogance, selfishness and self absorption, thinking they are always right…
Look for someone who is kind and generous. Its not so hard to see someone’s nature if you spend enough time with them. Test them out by going out of your way to do thongs for them. See if they thank you and see if the thank you is sincere and expresses true appreciation.