Don't you hate the oft repeated shrugs, nods, and smiles in novels?
Describing body language in writing can help readers visualise a scene and get a feel for the characters. They can also help writers avoid a string of he said, she said, he asked, and other dialogue tags that can become repetitive and boring.
The Top Five Tips For Using Body Language
Use body language to add depth to dialogue.
Use it because more than 50% of human communication is non-verbal.
Use it to show how your character’s emotions affect their actions.
Use it to help you show rather than tell your reader everything.
Use it in moderation. If overused, it can slow your story down.
Here's a body language cheat sheet to help you avoid repetitive, meaningless character actions in your writing.
Handy for editors too.
Sources: https://www.bryndonovan.com/2015/04/10/master-list-of-gestures-and-body-language-for-writers/
https://www.writerswrite.co.za/cheat-sheets-for-writing-body-language/#:~:text=The%20Top%20Five%20Tips%20For,than%20tell%20your%20reader%20everything.