First drafts are allowed to be terrible, but compared to the final masterpiece you will produce, they shouldn't be as terrible.

If you're a beginner, you need to give yourself permission to write terrible first drafts in order to get the practice at writing that you need to become better. If you're a professional, your first drafts shouldn't be as terrible as all that.

Think of a signature gesture that communicates your character’s general vibe — anxiety, comedy, power — and show them doing this. 

Now think of the first thing about them that strikes your senses — do they smell amazing or terrible? Have they tightly curled, wild-looking hair? A voice so soft you have to lean in to hear? Draw inspiration from people you know or people you see on the street for extra originality. Avoid taking inspiration from famous people/characters.