Bernie - A good entertainer/emcee will look at the crowd to "read" them. Their faces, body language, and possibly, breathing will tell you what they want. As a general rule, people don't expect a lot of yapping between songs, but friendly, thematic tidbits can help "connect" you to the audience. Pick a face, and talk TO them. For example:
"This next song was inspired by that lovely lady in red, over by the water fountain. Let's all share it together"
Breathers are ok after long medleys, or fast tunes, but don't let the airspace go dead - interact and let them know you're taking that break for their benefit.
ie:
"Whew ... you guys have so much more energy than I do! Beautiful job - I'd only be able to finish half that dance - well done! So ... here's a nice slow dance. Pick a partner that's fun to hold close. (big smile)"

Let the crowd tell you what they like. They always do. If you come across as sincere, they will warm right up to you. Let the music speak for your emotions.