John 7:24 Judge not according to the appearance, but judge righteous judgment.

Matthew 7:1 Judge not, that ye be not judged.

Judge not but judge. So exactly how do we do that? How I do it might not be right, but it works for me. In verse 7:23 Jesus said “If a man on the sabbath day receive circumcision, that the law of Moses should not be broken; are ye angry at me, because I have made a man every whit whole on the sabbath day?” I judge verse 24 to mean this: God is at work here.

John 5:19 Then answered Jesus and said unto them, Verily, verily, I say unto you, The Son can do nothing of himself, but what he seeth the Father do: for what things soever he doeth, these also doeth the Son likewise.

My judgement is supported by this scripture. Jesus sees God the Father at work and joins Him in that work. For me, I try to see in any circumstance if God is at work. That is the first judgement, the second is to judge if anything I might do is a help or a hindrance. It took me some time to learn how to judge the second part. Giftings and talents may train you to do a work for the Lord but when and how ends up being a matter of experience.

John 7:16-18 Jesus answered them, and said, My doctrine is not mine, but his that sent me. If any man will do his will, he shall know of the doctrine, whether it be of God, or whether I speak of myself. He that speaketh of himself seeketh his own glory: but he that seeketh his glory that sent him, the same is true, and no unrighteousness is in him.

A good place to start is in the motivations of your heart.