How do you find your type?
Trial and error.
Ask people you know what their first impression of you was. Find the common characteristics that multiple people say about you. Watch films with those character types and imagine yourself playing those roles.
What feels best?
Even if many people see you as one type, you have to be comfortable playing those roles. Try a few types out and see what is the most fun to play and what you feel you could make a long lasting career out of.
What do you excel with?
Play these character types in front of people who know you and see what their impression is. If you play that type of character and it is believable, keep honing in on these skills and make it of upmost importance to master this type.
Then you can market yourself as that type of character.