Relatability is key. Holden Caulfield from 'The Catcher in the Rye' is a great example. Many readers can identify with his sense of alienation and confusion as he transitions from adolescence to adulthood. His raw and honest voice makes him seem like a real person that readers can connect with on an emotional level.
A character who drives the plot forward in an interesting way can be considered one of the best. Frodo Baggins in 'The Lord of the Rings' is given the huge task of destroying the One Ring. His journey is filled with danger, self - doubt, and moral challenges. His decisions and actions not only shape his own fate but also the fate of the entire Middle - earth, making him an unforgettable and excellent character in the novel.