I have a young friend, an undergraduate at the Ivy League U. where her parents (and my husband and I) all did graduate work, who has developed an interest in graduate school in English or a related field. Since no one really likes unsolicited advice, even from people who aren't related to you, I thought I'd blog mine instead of boring the pants off her.
She is very bright, talented in multiple fields, good at languages and mathematics. In fact, this interest in English is a bit of a surprise. She's good at it, but many of her older friends and relations expected her to be a mathematician or physicist.
Given this background, I begin the unsolicited advice:
1. Don't go to graduate school right away.
2. Use your skills in math and languages to get as lucrative a job as possible. This probably means finance of some variety. You want both money and work experience outside the academy: something to fall back on if you don't get an academic job, and also very useful if you develop an interest in academic administration. People who understand money and the business world are valuable in academe.
3. Work for 5 years. Do not tell anyone at work you plan to quit in 5 years and go to grad school.
4. Save all the money you can. Open a retirement fund immediately and put in all the money you're allowed to. If people wonder why you're living way under your means, tell them you're paying off student loans, or paying your grandma's medical bills--anything sympathetic and plausible. You want a cushion when you start grad school.
5. This is a good time to get married if you have someone around; then you can stay home with him and save money rather than going out with the high-rollers. Make sure your husband is portable.
6. While you're working, read all you can. Read novels, plays, poems, drama. Go to plays. Read criticism, too. You'll re-read a lot of these texts in class later, but you might as well get a lot of reading done now.
7. If you need more languages, start working on them. If you need a modern language, see if you can get your employer to send you to that country to work. If you need Old Church Slavonic or something, that's more problematic, but still, do what you can.
8. After 4 years, take the GREs, research schools and departments, and apply to the places you want to go. Books and other blogs can tell you how to do this.
9. After 5 years, quit and go back to school at the best place you can get funding. Supplementing your stipend with your savings will allow you to live like a human being. All the reading you did will help you stay on top of things.
10. If you want children, have at least the first one while you're in grad school. A few older profs may doubt your seriousness, but mostly people have accepted that women can have children and careers. You're still younger and more energetic than you will be later; your time is flexible; and you probably have friends around who either have kids or would like to, who will help with babysitting. Then when you start a tenure-track job and are worked to death, at least one kid is potty-trained and so ready for pre-school.
11. If going abroad for research purposes would be a good idea, DO IT. This, too, gets harder later. Making contacts now is like starting a retirement account early.
12. Do not leave town to write your dissertation elsewhere. Stay near your advisor so you'll get attention.
If everything works out right, you'll get a tenure-track job in your early 30's and be tenured by 40. This is a little older than the wunderkinder who rush straight through, but not crone-aged by any means. And if it doesn't work out, you have work experience that will help you keep some perspective on the whole thing. Of course it's hard to go back to any career you've been away from for 6 years or so, but it's better than knowing only school and having to develop a completely new career path from scratch. You know you can make a living at something else, which will make you more confident, which in turn may help you get the academic job you want.
Obviously much of this advice is specific to someone with a great deal of cultural and intellectual capital. You don't have to have all of my young friend's advantages to succeed; you don't have to follow my suggested career path, either. But in the best-of-all-possible-worlds, such a path seems to me the most likely to lead to a happy, successful, productive life.
Your mileage may vary.