on Writers Helping Writers:

Conflict is very often the magic sauce for generating tension and turning a ho-hum story into one that rivets readers. As such, every scene should contain a struggle of some kind. Maybe it’s an internal tug-of-war having to do with difficult decisions, morals, or temptations. Or it could come from an external source—other characters, unfortunate circumstances, or the force of nature itself.

Whether you’re looking for minor friction options for a given scene or major conflicts to hamper the character’s overall story goal, this thesaurus can help. Think about what your character wants and how best to block them, then choose a source of conflict that will ramp up the tension in each scene.