The first story I was assigned on the topic of Christian music, back in the early ’90s, was an investigation into whether Christian bands used religious talk shows the way mainstream bands boosted their records on the “Tonight” show or Letterman.The answer? Not really. But it occurred to me while watching Switchfoot perform “Mess of Me” on the “Tonight” show this week–above, I embedded their “Kimmel” appearance from two weeks ago; it was hotter–that when Christian record producers first dreamed of bands that could play both on mainstream TV and at Christian festivals, Switchfoot was what they pictured. How did they do it? Some lessons of Switchfoot’s crossover success:Build a Christian audience first. Though bands hate to be restricted to Christian CD racks, gospel Grammys and CCM radio–one group of rocking believers sued their mainstream label when they were shunted to the Christian subsidiary–church basements and Christian festivals give a band a safe place to tighten their sound and find their voice. Think Beatles in Hamburg.Get riffy with it. The crossover rock bands of the ’90s tried to translate their Christian numbers into mainstream success without getting a grip on what drives the secular market: aural hooks to fight through the bigger, noisier crowd. From “Dare You to Move” to “Hello Hurricane,” Switchfoot has stripped down from alt-jangle to a sound centered on gritty riffs.Stay Christian. While they adapted to mainstream sound, Switchfoot has never stopped writing songs that make sense to both its audiences, unlike bands that tried to smuggle themselves across the Christian divide with secular pop. Even when they hit, they soon died because they had stopped doing what made them good. Witness “Mess of Me,” which screeches about drugs and misspent days, but is ultimately about redemption.