Good Eye Contact
Gazing ( not staring ) into someone's eyes is a good sign

Leaning forward
Making the space between you tow smaller and more cozy signals that interest is on the way up and walls are on the way down.

Relaxed Posture
Sitting or standing comfortably, breathing smoothly indicates that your date is open and non-defensive.

Palms Up
Open hands indicate a warm and receptive heart.

Touching
If the touching is warm rather than suggestive, contact is being made.

Nodding
If your date nods periodically as you speak, you're on the same wavelength.

Mirroring
Unconsciously reflecting each other's behaviour - leaning forward at the same time, breathing in sync, corssing the same leg over the other at the same time, speaking in the same tone - says that you're atunned to one another.

Synchronization
Simultaneous breathing, blinking and shifting in your seat means you're in sync.