1. Have a character release a balloon into the air
    This one is an old standby. A tried and true gem. It can be when a lovable but flawed protagonist does something unforgivable and their family might find out, or when a child loses their innocence after witnessing a murder or shoplifting or giving a handjob for the first time. Really hard to go wrong with this.
  2. Rack focus from a criminal in a church to a stained glass picture of a saint.
    Guaranteed home run here. Criminal trying to go straight after "one last job?" Conflicted mobster? Repentent embezzler with a spouse and a kid? Plop 'em down in a pew and have a just out of focus saint whose personal journey coincides with them in the background. Then, right when you're about to cut, rack focus, baby!! We'll see that saint clear as day and we'll know that this whole thing is probably a parable for the 4 years you spent in catholic school.
  3. Place your protagonist (who is looking for an escape) around lots of nautical imagery.
    The choppy surf! The high seas! International waters! No rules, just you and some crystal clear ocean. If your characters are trapped in a situation looking for a way out, throw a paddle up on the wall behind them at a bar. Give them a spyglass or a seahorse necklace. Have them gaze out onto the pier or play the trumpet wading in the water at a lake 4-5 times. We'll figure it out! When they're taking off into the sunset on a rickety old schooner at the end, we'll be like "ohhh I get it!!'
  4. Give your prostitute character a Virgin Mary figurine that she clutches constantly.
    This one's VERY solid. No need to explain! Just toss it in there and wait for the Independent Spirit Awards to roll in. You're welcome! Just don't forget to thank me in your acceptance speech! Right after Harvey and Bob ;)
  5. Have your protagonist look at the reflection of a bottle of painkillers in the mirror
    Suggested by @Waz