Creating characters for your audience not yourself

I just finished working on a story. I had so much fun writing this piece because my protagonist took control of the story and the dialogue. I asked a friend and fellow writer to read it. She came back with great feedback. As a reader, she expressed exactly what I was looking for: a reaction about my character. Giving life to a character is sometimes a difficult task. We, the writer, must detach completely from our characters so they can take on a life of their own, so they can have an impact on the reader.
Here are a few pointers for creating interesting and unforgettable characters:

Leave your ego behind and be modest. Think of your character as a voyage into the unknown. Don’t assume you know him/her. We don’t know people thoroughly, not even our own husbands/wives or family members. So approach your characters with that in mind. If they are mysterious to you, they'll be mysterious to your readers. Isn’t that wonderful?

Be open to new possibilities. Let your key characters say unusual things, things that you wouldn’t say. If you use curse words, let your characters do it only at the appropriate time and appropriate scene. If you overdo the swearing you’ll lose your readers. Let your characters be out of your control. They have free will just like we do. They have to surprise you so that this effect is transferred to your readers.

Remember that your characters are not your children; therefore, they do not have to bear obvious resemblance to you. Even if your characters are inspired by some aspects of your personality, they don't have to be your mirror image. It would be more interesting if every attitude and opinion of theirs was contrary to yours.

When things happen to you unexpectedly, you respond in a certain way. So this will be the case for your characters in your story. Let them react, not as you expect them to, but as they choose to. Don't control them.

Remember characterization allows us to empathize with the protagonist and secondary characters, and thus feel that what is happening to these people in the story is vicariously happening to us.