Choosing a major professor
Advice sent to an aspiring grad student, without identifying particulars.
1) Don't use a generic subject line when contacting a prospective major professor. I almost didn't open your email, thinking it was probably spam. Snail mail with a stamp and handwritten address really stands out, but email with "reprint request" will probably be opened. Ask for a PDF of a paper or two whose abstract looks interesting, but you don't have full-text access.
2) Read the papers, plus others you can find on-line or in your nearest university library. You might also consider going to a relevant scientific meeting in addition to, but not instead of, reading scientific papers. The nice thing about a meeting is that you can ask questions and talk to people from lots of different labs all in one place. The problem with talks is that if something isn't clear, it's gone, whereas with a paper you can read it twice, think about it, look up relevant definitions, etc.
3) Do the papers (including the part about weighing 5000 seeds or chasing lizards in the rain) make you think "I wish I'd done that?" If not, look for another lab, that does make you react that way.
4) Send your top few choices an email labeled "prospective grad student." Include enough detail from the papers so it's obvious you have read them with interest. (I trash emails saying "I'm really interested in your work on molecular biology.") Include information on any undergrad research, GRE scores, etc. Ask about opportunities to work in his or her lab.
5) Apply to those schools that seem most promising. Don't miss deadlines! Deadlines for fellowships may be earlier than those for admission. Having a professor who wants you really increases your chances of admission, though not necessarily of fellowship support.
6) Narrow down your choices. If someone has a research assistantship in hand, you may need to commit to them, if you want them to commit to you. Otherwise, it's common to apply 2-4 places and see who comes through with financial support. Don't make the mistake of picking the biggest assistantship over the most interesting project, but don't go into debt.
7) Try to visit each school before deciding. Perhaps because word about the shortage of faculty jobs has gotten around, the most promising grad students are actually in short supply, relative to demand. Unfortunately, demand often means professors wanting students, rather than professors having money to support students. If you're among the most promising applicants, they may invite you to a recruitment weekend and pay your travel costs. If you go, be sure you know what the several faculty nearest to your interests are doing at each school, not just the one you are most interested in. (If there's an unexpected personality conflict, will there be any other options there? Also, this makes you seem better prepared.) Talk to current students. Are they enjoying grad school, mostly? Are former students getting the kinds of job you would like?
7) Once admitted, see if you can start your research the summer before you start classes. It's a lot easier to keep experiments (or serious reading) going in the limited time between classes than it is to start them.
8) Don't get discouraged if your first experiments don't give clear results. This is normal. Figure out what went wrong and fix it, if possible, or try another approach, or try a slightly different question. If setbacks really upset you, consider another career.