R’ Gavriel Friedman suggests that before you speak loshon hara about someone, first write down everything you want to say including all the juicy contents. When you are done, then take out another piece of paper and write the words “Olam Habah,” “Eternity” and “Relationship with Hashem.”
Put the two pieces of paper next to each other and look at them. Then speak loshon hara if that is what you want to do. But make a choice! Don’t just give up eternity without choosing to give up eternity! Make a choice!