In regards to wearing good clothes when one fills out an application, may I just add a huge and loud "YES!" My father always taught us to dress up so we did. This has stayed with me all my life, but when I once applied to FedEx it was especially apparent why.
FedEx ran a large ad saying they would be interviewing for drivers in our area on a certain day. They wanted us to come to a certain location at a specific time. I was the only woman out of about three dozen applicants. We were herded into a large room with about eight rows of rectangular tables and chairs. When the two women--both dressed smartly in business suits--came up to talk about the application process, which is insanely complex, I took the opportunity to look around a bit and confirm my surprised analysis that I was the only one in a suit. It was a dark blue knit one with a button sweater jacket and straight skirt so it was comfy but nice. One man who may have been a few years older than I wore dark pants with a white shirt and nice tie. No jacket. Everyone else was in jeans, t-shirts, even shorts. I was amazed.
Though I had no experience in the area, I was one of only six invited for an interview immediately afterward, and I later found out I was one of only two offered a position. I simply could not believe that people didn't take the application meeting seriously.
A second piece of advice I got has always proved useful, and that is to get there early, park out in a place--around the corner, down the block--where you know you can't be seen--and do your final checks there. Once you are even possibly, remotely within sight of anyone in the company don't do any of that. Just turn the engine off, get out of the car, and walk in. You'll look and feel supremely confident. (And I always have.)