Image from Giphy.com. Shot from The Hunger Games.
(Optional) Add Trinkets and Quirks
This is one of my favorites. Add a fairly random item to your character’s inventory, and then ask yourself why your character would have that item on their person. It may force narrative, but it is both fun for the writer, and it makes an interesting character history and aspect overall.
Add this with a quirk if you can for even greater effect. A particular character in One Piece basically defines character quirks for me. The character is a butler who always pushes up his glasses with the inside of his wrist. This hints as his use of scissor hands as weapons.
If done well, trinkets and quirks can easily amplify a character in small ways.