Rachel Barbanel-Fried, PsyD, remembers how torn she felt when, as a third-year clinical psychology student at George Washington University, she had to turn down the opportunity to train summer camp counselors. The thought of spending time at the camp she'd worked at for years was tempting, yet she was already overwhelmed with studying for her comprehensive exams and knew she needed to find a summer position that was more related to her future career aspirations. She had to say no.

"I felt like I was going to drown if I said yes," recalls Barbanel-Fried, now a clinical psychologist in private practice in Washington, D.C.

As a graduate student eager to make a name for yourself, it can be tough to pass up an invitation to serve on a student board or join an innovative research project. Even when you don't have the time to take it on—or don't want to—you may fear you'll offend a professor or that another opportunity won't come along.

But adding one more accomplishment to your vitae isn't worth neglecting your dissertation, internship applications or course work, says Gerald P. Koocher, PhD, a past president of APA and dean of the School of Health Sciences at Simmons College in Boston. The key is to set priorities, he says, and consider how each activity could complement your goals or advance your career.

"You have to look at these opportunities as a buffet where you are carrying a 6-inch plate," Koocher says. "You might want to pile on the ice cream and cake, but it's more important that you get the protein and veggies, and remember that you can come back for more."

He and other seasoned psychologists advise students to learn early how much they can manage and what opportunities are worth carving out time for. Here are their tips for learning how to say no when your plate is full:

• Bide your time. Unless a request is time-sensitive, it is usually acceptable to consider the prospect for a few days, Koocher says. Thank the person for offering the opportunity and let him or her know that you need to consult your schedule or talk to your adviser before you decide. Be clear about when you will followup—perhaps by the end of the week—and make good on that promise.

• Gather all the details. Ask how much time the opportunity will involve, and survey people who've been in the role to see if their answers match, says Koocher. For example, if you're offered a research assistantship with a professor, ask other students how they fared working for him. "It may turn out that this guy's students take 10 years to finish the program when everyone else's students finish in four," Koocher says.

• Assess your goals. Consider whether the position might allow you to work with a population you haven't worked with before or use a new instrument—be it a psychological test or technological tool. If so, it may be worth finding the time for, Koocher adds. For example, students bound for research careers can get great experience spending a year helping to review journal articles, as opposed to spending a second year on their school's student ethics committee.

• Make a pro-con list. Chicago clinical psychologist Ritu Trivedi-Purohit, PsyD, suggests doing a cost-benefit analysis to help you figure out what to turn down when you're overextended. "In the immediacy, some opportunities may appear to be golden and there will be things that you don't want to give up," she says. "If you maintain a long-term focus, weighing the costs and benefits, you will be able to make these tough decisions and take things more in stride."

• Get the big picture. Ask your adviser, supervisors and mentors if you should make time for the opportunity. Often, they can help you keep your broader objectives in mind, says Nicole Perez, PhD, a clinical psychology intern at the Medical University of South Carolina.

• Be polite, but firm. If you choose to decline an offer, respectfully emphasize that your schedule won't allow you to give the position or project the attention it deserves. "I would much prefer someone to say they couldn't take something on than have them say yes and then not deliver," says Barbanel-Fried.

• Offer alternatives. If an offer really is too tempting to pass up, see if it's possible to negotiate a more reasonable amount of involvement. If not, keep your name in the game by asking to be considered when you have more time, Perez says. Or, suggest someone else for the position—that shows how much you respected the offer, Koocher says.

"Learning how to say no is an art form," he explains. "The key is to make sure the person doesn't feel rejected."