Requirements for College

There are so many different requirements for a physician assistant college that I am wondering why there are not more standardized requirements for them. Although most of the schools do require the initial 2 year degree for undergraduate studies, there are different requirements to get into the school. So after I get my 2 year schooling in what should I really concentrate on to get into the college of my choice? Is there something in particular that looks better on your resume than anything else? I really want to be a physician assistant and I want the best training available.