It can happen at any time and look many different ways. When reading your favorite blog your eyes might linger at the number of followers they have and mentally sigh at your own readership. Walking to class on the way to a final you spot the pretty blonde looking all spiffied up and fresh out of a magazine, not to mention three boys in tow. At your weekly Bible study you share your opinion but your neighbor voices a thought or insight that everyone swiftly writes in their journal. Your best friend gets the lead in the play you want when you auditioned at the same time. It can happen any time, anywhere.
Comparison is believing the lie that we are unequal and of different values to God. Comparison is ranking those made in God's image according to worldly standards. Comparison steals your joy and denies your identity. Comparison leads to no fruit.
This verse is one I am trying to memorize and one that has resonated in my heart these past few weeks. It is from The Message, which is a poetic paraphrasing, but it shares the heart of God so well.
Second, combat the lie with truth. Memorize scripture. Print it out, write it on a sticky note, put it in your car or on your mirror. Wherever you find yourself struggling with it the most, put God's Word in arm's reach or have it ready in your heart and head. In the New Testament with Jesus was tempted in the desert, He refuted the devil with the Word of God.
Third, know your identity in Christ. Know it and believe it. He is the one who assigns your worth and value. And He calls us worthy and valuable. He paid any penalty and cost by sending His Son to the cross. Donald Miller tweeted this a few weeks ago and I suggest saving it to your phone for reference when you're feeling down, doubtful, or struggling with comparison.