Having done the PhD advice, here's my advice for people (particularly Episcopalians, particularly ordinands) starting seminary.
1. Much agony can be avoided by not confusing your seminary with your parish. Seminaries should be (or should aspire to be) prayerful and supportive Christian communities, but they are also unwieldy institutions of graduate higher education. Find a church and go there weekly.
2. Pray every day. Episcopalians, pray the 1979 Daily Office every day. Supplement it with other ways of praying if you like...1662, centering prayer, Book of Hours, whatever. But start by learning to pray the way you will teach your church to pray.
3. No one does all the reading. You do not have to do all the reading.
4. There will be classes that are really exciting to take, and classes that will help you in your ministry. These aren't always the same classes. I still regret taking another political theology class instead of Bible Study in the Local Church.
5. At the same time, no one learns everything they need to know for parish ministry in seminary. Try community college or online offerings in accounting, fund raising, graphics, etc. Make intentional use of Field Ed as a time to learn about administration and leadership.
6. Be aware that you are getting tossed into an environment that lends itself to emotional intensity: study of God and the church, vocational uncertainty, the social and political turmoil of our society. Find tools to cope. You don't always have to have hot takes.
6a. Seminary is also an environment that - I think rightly, like boot camp - pushes people up against their limits of endurance. Figure out how you break, and put in guardrails for yourself so you can cope under pressure in ways that work for you. Discover your besetting sin.
7. Field Ed is a time to learn from lay leaders as well as clergy. Especially the Altar Guild.
8. CPE group work is a good time to learn the art of 'strategic sharing': being just vulnerable enough, but not too much.
9. There is a body of knowledge that you should leave seminary knowing. God is the truly interesting part of Christianity, and you should be able to teach and preach who God is, how God has acted, how God continues to act.
10. If you're going to share the Gospel with others, you need to hear it for yourself, as good news for you, first.
11. One of the hardest transitions in seminary is learning that ministry is both about you and not about you. No one will be a priest exactly like you will. Being a priest is full of joy, but it is not a means towards your own self-actualization.
12. Find mentors, experienced clergy and lay people who are doing Christianity and ministry in ways you want to learn from and emulate. Know that you may not want to emulate them in everything, and that's OK.
13. Counseling and spiritual direction can also help you get clear about #11.
14. Being on Twitter is good practice for living in a rectory next to the church where people can see in your windows.
15. Read the ordination vows and declaration of conformity regularly. Ask yourself, "Are these the promises that I want to keep (always straying, always repenting) for the rest of my life? Do they feel like a home, or do they feel like a cage?"