Well their face contorts in rage thats how you tell.
They are angry they loose temprethey falsely accuse they become passive agresive (like pharisees) you cant get anything done around them, they interfere with others, they are a nuisance and they always distract you from important work.
Just pray for them and be quiet and they calm down, then if they are christians the holy spirit tells them they are not acting like Jesus and they repent.
this is why early mornin worship is important each day to start out without demons.
Watch and pray thorugh the day in case one clamps onto you then you pray right away
you catch them from being around others with demons or by a gift or by a book that is written by demon author
If you have any books that are not christian on your bookshelf the demons are allowed to remai in your house all the time...
Records too. CD's and anythin demonic... they are allowed to come and o then.
When you clean house it becomse very peaceful...
Usually Jesus help me be ood, I am sorry
please keep me in your love
Psalm prayers work well
"Take not your holy spirit from me"
You see, Jesus promised anyone goin to Jesus in prayer will not be cast out
and when you go to Jesus in prayer the demons have to leave
so always go to Jesus!