Write down key words and carry them with you through the week. See that your pastor has the time needed to prepare. Make sure your congregation's budget includes money for books and advanced courses necessary to keep your pastor's intellect sharp. If the preacher is stimulated and well-equipped to navigate the mysteries of faith, sermons will be better. Ask questions if you don't understand.
Most pastors love when people ask questions.
It means they were listening. And it's all right to disagree as long as you keep the disagreement civil and helpful. Remember not all sermons are winners for every listener. On a particular day, the message might not be effective or relate to your concerns. The sermon that touched you two weeks ago may have sounded obscure to others.