To know if someone is interested in your conversation look at their feet, if their feet are pointing towards you, they are interested. If their feet are pointing in another direction (other than you), they aren’t.
Ask someone to trace an uppercase E on their forehead using their finger. If they draw it so you can read it, they’re doing what’s best for you and are generally empathetic. If they draw it facing themself, they are generally thinking of him or her self and aren’t generally empathetic.