I always get the audience involved and play some songs they can sing along with ... "When You're Smiling" "You are My Sunshine", "My Blue Heaven" or get them to sing the title or 'hook' phrase, like "... The Wonder of You", "... keep away from Runaround Sue", "...Bad, bad Leroy Brown" ... "Sweet Caroline - 'whoa, whoa, whoa ... so good, so good, so good" ... etc. I had them singing "Go Johnny, Go" ... on Saturday ... you get the idea ... I will stop singing and even lower the volume of the KB so that they can hear others singing along as well ...
I also keep everything pretty much 'up-tempo' ... lots of 'shuffle' styles ... even ballads I will play at about 90 - 96 BPM ...
You will find that people in NH/AL centers are the MOST appreciative audiences you will play for, and even in lock down alzheimer's units, your music will bring back a memory and they will sing word for word along with you ...
Have fun, and they will have fun, and it will be the fastest hour of the day ...