It’s almost impossible to ruin a cast iron pan! That said, it does require a bit of patience as do all good things in life. What makes cast iron so perfect to get brown crusts and crisping is that it holds on to heat very well. However, on the flip side, it does take a bit longer to get the pan hot. Avoid trying to speed up this process by putting a cold pan on high heat- especially if your gas stove is electric! Sudden changes in temperature and uneven heating (using a coil-type or electric burner that is too small), if done over and over, may warp the pan.