Be perfect, therefore, as your heavenly Father is perfect.
So...how does one be perfect "like" God is perfect? What is God like?
1 John 4:16
... God is love. Whoever lives in love lives in God, and God in him.
So...to be perfect, you must love. So, let's take Paul's description of love and insert ourselves into it so we can guage how close we are to being perfect as our heavenly Father is perfect.
Does this ring true for you?
1 Corinthians 13:4-7 (individualized)
I am patient, I am kind. I do not envy, I do not boast, I am not proud. I am not rude, I am not self-seeking, I am not easily angered, I keep no record of wrongs. I do not delight in evil but rejoice with the truth. I always protect, always trust, always hope, always persevere.
When it's true for you, you are there.