Do you walk around thinking about your frizzy hair, height, eye color, etc? Exactly. So while you could give a descriptive dossier of your character, it will have no meaning, which means the reader won't care. But there is another option.

Have your characters react to each other. If you have one character say the other is a jerk while the other is doing something absolutely innocent, for example, that will say something much bigger about both of the characters. 

Think about it this way: if you only just met someone and they told you, "I'm the best person you're ever going to meet. I'm so nice," would you really believe them? Probably not. But if their friend walks up and tells you a story about how this guy saved someone's life once, your opinion of that person would likely go up. 

Consider how you can use various reactions to your benefit, particularly when your story starts. 

,This is a piece of advice I learned from Lisa Cron's Story Genius, which is in my top 5 best books on writing. (You really should buy it.) 

MISBELIEF. People carry beliefs about themselves, and they're not always true. The same can be said for characters. If you can define a character's misbelief about themselves, then it can drive an entire novel. For example, one of my own character's misbeliefs is that he isn't good enough. Things happened in the past to make him believe this. But through my story, he slowly comes to understand the truth about who he is. 

Although Story Genius talks about using this with the protagonist, I use this with every one of the characters in my novel. It's a powerful device that moves beyond mere "want" and "desire."