Here's an excellent resource, particularly aimed at people in Christian ministry. It's a series of podcasts from Sovereign Grace ministries - the one on joy was, in my opinion, excellent. The great focus of this ministry is 1 Tim 4:16 "Keep a close watch on yourself and on the teaching." Here is an excellent talk by Cj Mahaney on this verse. This is obviously really important for anyone but particularly so for those of us in ministry. I've just been re-reading Richard Baxter's The Reformed Pastor. He exhorts pastors to 'take heed to themselves' in ministry, to constantly examine themselves and keep watch over their hearts and ministry. His reasons are sobering....
(see Chapter One "What is it to take heed to ourselves?")
1. "...lest you be void of that saving grace which you offer to others...And lest while you proclaim the necessity of a Saviour to the world, your own hearts neglect Him and cause you to miss an interest in Him and His saving benefits....God never saved any man for being a preacher, nor because he was an able pracher."
2. "...lest you live in those actual sins which you preach against in others, and lest you be guilty of that which you daily condemn...If sin is evil, why do you live in it? If it is not, why do you dissuade men from it?...It is easier to chide at sin than to overcome it."
3. "...that you may not be unfit for the great employment you have undertaken. He must not be himself a babe in knowledge who desires to teach men all those mysterious things that must be known in order to be saved..."
4. "...lest your example contradict your doctrine...lest you unsay with your lives that which you say with your tongues, and thus be the greatest hinderers of the success of your labours....It is a palpable error in those ministers who make such a difference between their preaching and their living. They study hard to preach exactly, and yet study little or none at all to live exactly....we must be doers and not preachers only...we must study as hard how to live well as how to preach well."