Trying to change someone is a waste of time. The very thought of changing someone is saying that they're not good enough as they are, and it's soaked with judgment and disapproval. That is not a thought of appreciation or love, and those thoughts will only bring separation between you and that person.
You must look for the good in people to have more of it appear. As you look only for the good things in a person, you will be amazed at what your new focus reveals.