Graduate school is not for everybody. Don't agree to a school just to "get in" somewhere, and don't accept if you're not really sure you want to go there. Be aware of your chances of acceptance if you reapply; grad school is competitive and all departments vary in what they can offer. Take some time off; you could keep busy by volunteering to help grad students or professors collect data, take a few classes at the graduate level in a nearby university/college, or work at a field station or laboratory. You'll get experience, meet other scientists, and it could even get you some publications. Undergraduate fellowships or internships are often available which pay a modest stipend and/or room and board. You might not get rich, but you'll have a better idea whether grad school is for you & learn valuable experience to make you a stronger candidate when you apply again!

1. Figure out what, in general, you are interested in studying.
2. Take the GRE general and subject tests early enough so that you can retake it/them if you did poorly the first time. Study guides that reproduce past tests are available in many bookstores. Tests are offered in the spring and fall, but many upper tier schools do not accept scores from the December test (received too late for January decisions), so many seniors will need to take the October test (registration for the October test is the first week of fall semester).
3. Read through journal articles and books published by people you would like to work with, or who study things of interest to you. Pay greatest attention to recent publications.
4. Identify particular people, labs, departments, or universities with a strong emphasis on your research topic(s). Most undergraduate universities have bulletin boards that display fliers and postings from graduate schools. Talk with people (TA's, grad students, professors) from your undergraduate institution; they can give you additional information (e.g., where to apply, how to apply, what to look for, financial support options, questions to ask).
5. Read through the accounts of those universities offering programs in topics of interest to you (whether it's ecology, evolution, wildlife, molecular bio, or marine science) in PETERSON'S Guide to Colleges and Universities (library Reference sections). Peterson's Guide also has info on number of applicants, percent accepted.
6. DON'T BE AFRAID TO CALL, WRITE, OR ASK QUESTIONS.
7. WRITE EARLY!!   Don't assume that stated deadlines are real. Many fellowship decisions may be made much earlier.
8. Write those professors whose work interests you. Use the Internet or Peterson’s Guide to find addresses and phone numbers. How many grad students do they have presently: lots (too many for individual attention?)? or few (are they new to the department?). Are they accepting students that year? How would they support you (financially) if you came? How well have past students done in the job market? are recent graduates employed or have post-doc positions?
9. Write, call or e-mail current grad students of those professors. This is very useful; professors may emphasize the good things about themselves and the department, and even when they are completely honest, their point of view may not represent that of a grad student. How well do they like the professor? his/her teaching methods? the department? the area?
10. Write to those departments that have specific programs of interest to you. Include a letter with your intentions (MS, PhD), a copy of your CV, and maybe an unofficial transcript. When is the application deadline? Request a Graduate School Information Packet. Get a list of requirements; which ones are flexible and can be waived under certain circumstances? Funding: is it guaranteed? for how long? is it dependent upon teaching? are fellowships and RA'S (Research Assistantships) available? Is summer support included? If not, what is available? Do current students think the funding is sufficient?
11. CALL those professors with whom you would like to work (with or without response to your letter).
12. Call those professor's grad students and other students in that department. Is it easy to work with that professor? What are his/her strengths and weaknesses (interpersonal skills, finding funding for grad students, project advice, connections)? what is the expected amount of work and research? how much time do students take to finish (courses, requirements, everything). On average, how much time does that prof spend with his students? Is he/she usually willing to make time for students? If it's a large lab, this is particularly important. Talking with grad students can be extremely helpful; only they can tell you what grad school and that department are like, what to expect, and how well everyone gets along.
13. Call the person in charge of graduate applications (often a secretary in the Biology office). Ask whether your file is complete, what's missing (especially your letters of recommendation, GRE scores, transcripts), and when decisions might be made.
14. VISIT, if possible.  This is not always possible because of time and/or money constraints, but make an effort to visit those universities nearby, and/or your favorite choice. Also, some departments will pay expenses for a visit of potential grad students. This is your opportunity to meet as many faculty members and grad students in the department, as well as to check up on your file status (complete, incomplete). It will also help them remember you during the selection process; it might give you an advantage over those who don't visit. Your potential advisor or his/her grad students may be able to put you up for a few days. How well would you fit in? Do you feel welcome? Are they enthusiastic about your potential arrival? Do you like the area? the University? the weather?
15. Don't give up!!  The decision making process often takes longer than you might expect. Call them if you're concerned, but don't be obnoxious about it. For example, if you're the fifth alternate on a list, they'll have to offer an opening to the four alternates above you, and be turned down by them before getting to you. This can take a while.