Get in contact with Jennifer Dill. She is (or was) the chair of the admissions committee. I applied there back in january and went and visited the school. I met with her and Ethan Seltzer, as well as James Strathman. All were very friendly.
I sat in on some classes and enjoyed what I saw. However, I realized (since I was visiting in January) that I would not be able to handle the winters in Oregon.
I was accepted, but without financial aid. Tuition there is ridiculously high for a state school, even if you are an in-state student.
I ended up going to (or staying at, as it would be) U of Texas at Austin. The program here is very different, but the weather is so much better. Plus, the out of state tuition here at UT is less than the IN STATE tuition at Portland State
As far is what is important in the application process...
I'd say two things: Letter of Intent and previous experience (internships, etc.) since most people there have been working for a while. Going up there and meeting with faculty couldnt hurt, either.