I usually go for asking questions. „Is this the most plausible reasoning?“ / „wouldn’t x be way simpler/cheaper/easier?“ The sceptic guide to the universe by S

I usually go for asking questions. „Is this the most plausible reasoning?“ / „wouldn’t x be way simpler/cheaper/easier?“ The sceptic guide to the universe by Steven Novella also has a short chapter on how to seed some skeptic thinking into others for them to reconsider their believe in conspiracies.