Choosing a program is the most important part of the process. Consider your career goals and search for a program that can help you achieve them. "Does this program lead me to where I want to go?" is a good question to consider.
Network with those in your desired profession to learn the path they took. There may be alternative programs to consider that you are not aware of. Weigh the strengths and weaknesses of the program. Consider faculty, reputation, location, affordability, and current students' perspectives.
Investigate schools of interest and set up a calendar of deadlines as an application timeline. Knowing and abiding by the process is essential. Some schools also have lengthy interview processes that you will need to prepare for. Career Services offers practice interviews that can be very helpful in this area.
Graduate school admissions processes vary considerably, depending on the field of choice and the prestige of the school in which you are applying. Check school websites for specific entrance requirements and processes.