"The Imitation of Christ" by Thomas a Kempis is a great book which I utilize as I use the Summa Theologica by St. Thomas Aquinas, I don't read them cover to cover, but read different chapters or passages based on a certain circumstance. It is free online here: http://www.ccel.org/ccel/kempis/imitation.toc.html
Here are some interesting passages I found today:
"So long as we live in this world we cannot escape suffering and temptation. Whence it is written in Job: “The life of man upon earth is a warfare.” (Job 7:1) Everyone, therefore, must guard against temptation and must watch in prayer lest the devil, who never sleeps but goes about seeking whom he may devour, find occasion to deceive him. No one is so perfect or so holy but he is sometimes tempted; man cannot be altogether free from temptation.
Many people try to escape temptations, only to fall more deeply. We cannot conquer simply by fleeing, but by patience and true humility we become stronger than all our enemies. The man who only shuns temptations outwardly and does not uproot them will make little progress; indeed they will quickly return, more violent than before. Little by little, in patience and long-suffering you will overcome them, by the help of God rather than by severity and your own rash ways ... The beginning of all temptation lies in a wavering mind and little trust in God, for as a rudderless ship is driven hither and yon by waves, so a careless and irresolute man is tempted in many ways. Fire tempers iron and temptation steels the just. Often we do not know what we can stand, but temptation shows us what we are."
On works of charity (love/agape/caritas):
"Without charity external work is of no value, but anything done in charity, be it ever so small and trivial, is entirely fruitful inasmuch as God weighs the love with which a man acts rather than the deed itself. He does much who loves much. He does much who does a thing well. He does well who serves the common good rather than his own interests. Now, that which seems to be charity is oftentimes really sensuality, for man’s own inclination, his own will, his hope of reward, and his self-interest, are motives seldom absent. On the contrary, he who has true and perfect charity seeks self in nothing, but searches all things for the glory of God."