Eye contact
Keeping eye contact definitely points to a sign of interest, connection, and especially intimacy. If your S.O.’s eyes dart around the room or even behind you, they could be preoccupied with something else other than what you are trying to express.
Darting eyes could also mean your S.O. is anxious. Also, keep in mind that most people are aware of their tendency to shift their gaze when they feel a bit anxious, so your partner might try to overcompensate by keeping their gaze fixed on you and blank.
Moreover, they might try to rub their eyes or even touch their face around their eyes when anxious. If you notice your S.O. scanning your body with their eyes, it’s a very clear sign of attraction and interest, especially if they don’t try to hide it when you notice the scanning.