If they take a sip of their drink, wait a few seconds and take a sip of yours. If they lean back, you lean back.
Most people focus on controlling their facial expressions, but they forget about their feet. Look at the direction their feet are pointing. Body Language Secrets: A Guide During Courtship...
These are "displacement activities" caused by the nervous energy of attraction. If your partner is constantly fixing their appearance while talking to you, they care deeply about your perception of them. 6. The Feet Don’t Lie If they take a sip of their drink,
Before a word is even spoken, your posture tells your partner if you are emotionally available or guarded. Look at the direction their feet are pointing
Watch for "preening"—smoothing out clothes, fixing hair, or adjusting a watch/jewelry.
Shift your gaze from one eye, to the other eye, then down to the mouth, and back up.