If you want to know when you are projecting your feelings onto another, one clue is negativity in the self, because projection is never neutral. It manifests as negative energy because what it is disguising is negative.
Other mirrors to the self include:
Humiliating others to hide your own humiliation.
Superiority disguises your feelings of failure and fear of rejection.
Defensiveness is so you don’t start attacking yourself.
Blame disguises feelings of fault and shame.
Idealizing disguises a weak, helpless child who needs protection.
Prejudice is expressed by those who feel inferior and who deserve rejection.
Jealousy is one’s own impulse to stray and paranoia disguises deep-seated, overwhelming anxiety.