Seasonally appropriate songs, especially of their time, are good. Right now, songs of Fall & school are appreciated. I always encourage singing along. Since the 1st vs is commonly what folks remember, but not the others, I commonly sing some songs verse & chorus through twice. Less embarrassment cause they don't remember the lyrics. Sometimes on a song they particularly seem to enjoy singing, we sing La, La, La as an extra verse in between 1st verses: "I know EVERYONE remembers the words to THIS verse, La, La, La . . ."
Often, when singing for the retirement home set, I pause & ask, "How many remember ____?" Then, ask some of them to tell their memory of whatever. I've learned some of my best stories this way. Once in Oklahoma, after singing "Them Old Cotton Fields Back Home," I asked how many had picked cotton when they were young. Many of the employees, most of whom were young, were shocked that I would ask such a question, & moreso when almost every resident raised their hand! I took the mic to a couple of nearby residents & asked them to tell a memory of pickin' cotton, the aprox year or their age then, the town. This is usually quite enjoyable for all. We can learn from the "old" folks, as they lived through a great deal more than we. By the way, I knew that most folks--such my mother & all 10 of her siblings, picked cotton for the desperately needed $$ in those hard times. AND, all of the residents in the audience happened to be "white."