There is so much good advice in this thread! I very recently finished up the application process (heading to a PhD program this fall), so although I can't say a lot about graduate work I can say some things about the application process.

1) I am very excited about the program I'll be attending, but I deeply regret how and why I decided to apply to graduate school: namely, I went into undergrad thinking a PhD program was the only thing I could ever do with my liberal arts humanities degree, and I got so stuck on that idea that I didn't explore anything else. There was also a lot of pressure from my family to apply to PhD programs, which made things harder. I might have explored other career paths and still decided a PhD was right for me, but because I didn't, I still doubt my choice.

I'll echo other people in this thread, though - if there's an opportunity for you to do an honors thesis or a senior capstone project or whatever, do it. First, a well-done project strengthens your application immensely. I got into 6 of 9 grad programs and at each one my potential advisors mentioned my senior thesis (which was mostly done by the time I submitted the apps, since at my school we start writing our senior theses as juniors). Second, it's the only opportunity you'll really get as an undergrad to do academic research and figure out for yourself if you're into it or not.

2) On a practical level, it's a surprising amount of work; most programs want a writing sample and a statement of purpose and those take time. I started writing my statements of purpose in July/August and had them finished by about September. My writing sample was the first 20 pages of my senior thesis, and I didn't have that done and polished until November.

Then there's stuff that's just stupid and time-consuming - one school wants front and back copies of your transcripts, another school wants electronic copies, one school has your recommenders send paper letters, another school wants them emailed to a graduate coordinator, the department website says something different from the graduate school website, etc. Being organized is really important; I kept everything on a spreadsheet, down to usernames and passwords for the online applications, and I probably would have died otherwise.

But I was mostly an emotional wreck, which I don't recommend; I actually ended up seeing a therapist (which turned out to be very helpful in a lot of different areas of my life). I took the success or failure of my grad school applications as referenda on my worth as a person, which meant that the thought of not getting into graduate school was absolutely terrifying.

3) History

4) I can't really speak to this, but if you're ready to go to grad school, then go. If you want experience in between and don't want to start a PhD program at 22, then I'd try to do something specific and concrete that can help you down the line - a job in your field, an internship, a Fulbright, teaching English abroad, etc.