If you're planning to go to graduate school, then choosing a PhD program is one of the most important decisions of your life. Though you're the one who will be chosen, on the merits of your application, there is much you can do beforehand to insure that you apply to the right universities.

You can plan on spending around seven years getting your doctorate, though that can fluctuate two to three years on either side depending on your discipline and program. So the school you attend will be a major influence on a large part of your life, and will determine the path of your future career as well. Most graduate programs are highly competitive, as is the job market you can expect upon graduation. It's a good idea to cast a wide net with your applications, to insure you'll have options.

Apply to as many schools as you can reasonably afford to, and actually want to attend if accepted.

Here some important factors to consider as you apply and mull your offers:

Funding

Acquiring decent funding is crucial. You'll be toiling outside of the regular workforce for years, so you're going to need a solid financial support package. Most graduate schools provide funding through teaching or research fellowships. That means that you'll be teaching one to two classes per semester or working as a professor's assistant to earn your keep. These packages usually include tuition and a stipend. Ideally, you'll get health insurance as well.

These stipends are not overly generous. You'll have enough to subsist modestly. Some programs have non-teaching fellowships, but these are usually competitive and awarded to few students for a year at a time. Many graduate students take out supplemental loans, especially if they have a family or merely want to live slightly better than a pauper.

Location

Since you might be relocating, it's important to take into account the characteristics of your potential new home. Do research on the city or town to get a sense of housing, neighborhoods, cost of living, and the general vibe. Don't forget to consider climate, especially if it will be a new one for you.

Achieving a doctorate is extremely challenging. It will go better for you if you at least like the place where you live.

Collegiality

No one has been able to predict which students will complete a PhD, and which will drop out (only about half finish). Studies also have difficulty predicting what factors help students succeed.

Nevertheless, students with a strong support system fair better. It's hard to gauge a department's temperament and style before you're immersed in it. Nonetheless, you need to find a department where you can thrive. If you visit, chances are, everyone will be on their best behavior. You still need to try and gain a strong sense of the environment and the level of collegiality.

Current graduate students can be a great source of information, as well. Most department websites publish email addresses. Don't be shy about writing your future colleagues and asking questions.

Research Compatibility

If you can't manage a visit, correspond with your potential professors, especially scholars who you may want to work with. You may not know exactly what your dissertation research will focus on yet, but you need to get a sense of how your interests will fair in that department. You'll need to have advocates and supporters. Look at the publications, research interests, and graduate student clubs or conferences to get a sense of your intellectual compatibility with your chosen department.

Completion Rates and Job Placement

Most departments have some kind of internal reporting that keeps track of completion rates and job placement statistics for graduate students. Don't be afraid to ask for this data. It won't necessarily impact your own job placement in the future, but it can provide some level of confidence and security as you make one of the most important decisions of your life.

Sources:

Cassuto, L. (2013, July 1). Ph.D. Attrition: How Much Is Too Much? Retrieved September 3, 2014 from the Chronicle of Higher Education.

Patel, V. (2014, February 17). To Improve Equity, Focus on Stipends, Graduate Students Say. Retrieved September 3, 2014 from the Chronicle of Higher Education.

Rampell, C. (2009, September 15). Thinking of Going to Grad School? Retrieved September 3, 2014 from Economix.