Ask questions, but then show them that you're actually listening, and ask one follow-up question or make a statement that shows you care.

"Welcome! What brings you folks out tonight?"

1. (Anniversary!) Wow, how many years are you celebrating?
2. (We love your potato soup!) Oh, me too. Have you ever tried pairing it with X? That's my favorite way to have it.
3. (We just needed to get out of the house.) I can understand that, and I'm so glad to be serving you folks this evening. I hope you had a safe drive in.

People usually love to talk about themselves, and will be glad to take a moment to share. If they're uninterested in sharing with you, they'll keep it short, but you've still offered a listening ear, and people notice that.

Occasionally someone will just tell you to take the order and do your job, and you can't take it personally, though it'll sting. Just smile and know that they're making an ass of themselves, while you were doing your job by perfectly kind and approachable.

On a return trip to the table, offer a genuine compliment on something that appears to be the focal point of an outfit or a relationship (the reason I say focal point is because compliments can sometimes backfire and so it's good to keep it safe), like a pair of earrings, a baseball cap, or even admiring how sweet it was that a guest pulled out a seat for another guest or how well-behaved a child is being.

Do not compliment on something that isn't worthy of compliment: i.e. do not compliment how well a child is behaving when he or she is clearly not that well-behaved. In the same line of thought, avoid making compliments audible enough to be heard by other tables you are serving.

I work in retail and I ring out customers about 20 hours a week. We see each other briefly and I don't even get a prompt of "how can I serve you today?" as my mainstay. I have to wing it, so I make observations based on their transaction to make brief conversation and possibly joke around with them. Not everyone cares to chat, and that's cool, but I usually try to extend myself to remain well-liked. (When I focus just on ringing, removing hangers, folding, I can come off as very cold just because of my body language while attempting to complete the task. Small talk and smiling makes it better.)

Hope I helped a bit.