Yes John 3:16 is not just plainly believing Jesus.
The Devil just heard the word of God and never keep it.
LUKE 11:28
28 But he said, Yea rather, blessed are they that hear the word of God, and keep it..
Therefore: To Follow John 3:16, follow Jesus how he followed Jesus Commandments:
JOHN 14:15
15 If ye love me, keep my commandments.
Jesus in his 1 body and having 2 roles (Role of the Father and Role of The Son)
In his Role as Son of God, who serve as MODEL he demonstrated how to obey or follow God's Commandments.
And how he did it is what Jesus expects us to do it.
Jesus revealed this to Peter.
1 PETER 2:21
21 For even hereunto were ye called: because Christ also suffered for us, leaving us an example, that ye should follow his steps:
Jesus in his role as Son of God, showed how humble he is when it comes to the word of God.
We all know that the Jews were amazed on Jesus Wisdom:
Jesus never committed to himself this wisdom in the eyes of God.
MARK 6:2
2 And when the sabbath day was come, he began to teach in the synagogue: and many hearing him were astonished, saying, From whence hath this man these things? and what wisdom is this which is given unto him, that even such mighty works are wrought by his hands?
Despite of that he claimed in the eyes of God that he knows nothing:
JOHN 5:19
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.
We also know that Jesus never committed Sins but look how he humble himself in the eyes of God.
He did not consider himself as GOOD.
LUKE 18:18-19
18 And a certain ruler asked him, saying, Good Master, what shall I do to inherit eternal life?
19 And Jesus said unto him, Why callest thou me good? none is good, save one, that is, God.
Who are the True Believers of Jesus who can follow his steps and consider Jesus as model and to claim John 3:16?