All of our hearts are idol factories . Richard Gaffin has said "Because we are, each of us, the image of God, we will worship, in fact we must worship, someone or something, either our original, as we should, or, with the illusion that we are the original or our own ultimate point of reference, ourselves. If the latter, we will give ourselves over, with the full, still efficient resources of our imaging capacities, to some figment, some distorted image, focused on ourselves or on some aspect of the world, ultimately seen as an extension of ourselves. What Calvin observed long ago is no less true today: the human heart, our image-bearing and image-fashioning nature, is an idol factory." (Richard Gaffin, "Speech and the Image of God," in The Pattern of Sound Doctrine: Systematic Theology at the Westminster Seminaries, Essays in Honor of Robert B. Strimple (2004), p. 186.)
As you may already know, here is some of what the bible says relating to our worship
1. The bible defines evil as the forsaking living water for broken cisterns; seeking to be satisfied in something or someone other than God Himself (Jer. 2:12-13).
2. Our worship of God is intended to bring us pleasure! “For it is good to sing praises to our God; for it is pleasant” (Ps. 147:1). God’s demand for our worship is a demand for us to be happy and to experience our greatest pleasures! If we are not worshiping God, it’s to our detriment.
3. The essence of worship is to find our deepest satisfaction in Jesus Christ alone — in this life, and even in the face of greatest loss and personal death (Phil. 1:18-23). We can be content in the loss of all things only if we treasure Christ above all else (Phil. 3:8). Further, to say that death is gain — because we long for greater intimacy with Christ — shows that Christ is the supreme object of our hearts. This is worship.
So the only way I know to make people move away from this all consuming fasination with celebrities is to make Christ and His Word more glorious by preaching it wil all the passion and earnestness I have and leave the results to God. Well, we don't make Christ more desirable but as the Word of God is proclaimed, God, the Holy Spirit, regenerates a person's life to give them a new desire for God. I don't really have a technique (which many seem to have today) but to show that it is idolatry to enjoy, love, and depend on anything or anyone more than God who is the most glorious being anywhere and call for repentance and faith in God through Christ alone. We shouldn't just say stop worshiping celebrities, but need to also say "treasuring Christ over things." Pleasure is the measure of our Treasure.
If you have time and the interest, I have found that this is a good series on this very topic: Idol Factory Sermons mp3 downloads or "Idol Factory" Sermons streaming audio