Luther in Large Catechism says something fascinating.

Therefore from youth on we should form the habit of praying daily for our needs, whenever we are aware of anything that affects us or other people around us, such as preachers, magistrates, neighbors, and servants; and, as I have said, we should always remind God of his commandment and promise.…This I say because I would like to see people learn to pray properly and not act so crudely and coldly that they daily become more inept in praying. This is just what the devil wants.

Inept means incompetent.  We are surrounded by so much incompetence in so many walks of life I was surprised in seeing Luther refer to incompetence in a prayer life.  The devil desires our prayers be as incompetent as a lot of the rest of our life is.  Luther of course has suggestions.  You can find them in your Catechism .