One characteristic of the sluggard is he doesn't follow through. He starts many things, but completes very little. Obviously you could get into trouble by being too stringent with this. (I'm thinking, for example, of a book you start but realize it's not the right thing for now). Nevertheless, our lives should be characterized by a commitment to finish what we start. "Whatever our hands find to do" we should "do it with all your might" until the thing is done (Ecclesiastes 9:10).
This probably seems like a trivial thing to write about. But I find not heeding this principle creates stress and stunts spiritual growth.