Spiritual manual for laypeople: Introduction to the Devout Life, by St. Francis de Sales

Few are the books with concrete instructions for how a layperson is to live the Catholic life; here's one of them: Introduction to the Devout Life by St. Francis de Sales. The great saint originally wrote it for Madame de Charmoisy, wife of an ambassador of the Duke of Savoy. Unlike, say, The Imitation of Christ which was written for religious, this guide was written specifically for people who wish to practice their faith while living in the world.

You must learn how to pass from prayer to the duties of your state…The lawyer must learn to pass from prayer to pleading a case; the business man to commerce, the married woman to her housework, with such gentleness and tranquility that the soul is not disturbed.

You can probably find a copy at a library or bookstore; good translations are also available online.