Warn Them About What's Coming
Just ask anyone. People don't usually say, "I want to go to Hell." One's final state comes into sharp focus when the reality of eternal punishment or eternal reward is presented...unless they are distracted.
If I put together a surprise birthday party for you, invited all your close friends, and catered your favorite food and hired your favorite band, in order for me to surprise you, I'd have to do everything possible to distract you until the last minute, the last few seconds before you walked through the door and everyone yells, "Surprise!".
There is no party waiting for anyone in hell. However the all too easy tendency to be luringly distracted by things which snatch away our focus from the only path that can keep us from such horror and anguish permeates almost every blink of the eye. When we step through eternity's door, it will be too late to refocus. At that point, we won't be able to start that new diet, say I'm sorry to the person we've held a grudge against, make the extra effort to be good in life,, or turn to the only person who can rescue us from Hell, Jesus.
If hell is real, and it is, why is there not unquenchable passion to keep anyone from going there from people who know this reality and care about everyone around them? How much do we have to not love someone to keep the reality of Hell from them? As Charles Spurgeon said, "If sinners be damned, at least let them leap to Hell over our bodies. If they will perish, let them perish with our arms about their knees. Let no one go there unwarned and unprayed for." I pray we as the body of Christ, we start becoming people who rescue others from the flames.