Having a great sense of humor helps a lot too. As well as building a rapport with your clients, find things and places they like to do and go to. Use that, familiar surroundings help them let their guard down and you can capture a more natural "them."
Don't be a robot, be yourself.
Like me, I do a lot of stuff for soldiers and their families. Being a soldier myself, there's a level of humor and antics I can bring to the table that I can't do with civilian families. Because I live that lifestyle, and can connect with clients better than most people can. But I've learned to adjust my humor and personality to fit the situation. But I'm never not myself.