It is a great idea to know how your institution markets the school. What is being, offered and what method, even to what market, i.e. demographics. 

It is vital to be prepared for an interview. Know the program details and know what to ask to ensure a productive sessions. Know what information can be shared to candidates and parents is essential, esp. when discussing tuition and fees, finances and financial aid. Recording keeping is a pivotal part of our job. Making sure the information provided is safe, stored correctly and disposed of in the correct manner, not only protects the candidate but also the institute as well. 

It is important to know the rules and regulations for an Admissions representative. Staying in the know as things change. Keeping a resource notebook. I, personally, have a notebook and a folder that I update as information changes, esp. withing my institution.