I have had plenty of experience with writing resumes because I did one while I was in high school. I didn't actually do one in class my older sister suggested to me to make one. So she helped me through the whole process. I trusted her that she was telling me the correct format and way to put together a resume because she just graduated from Suny Geneseo and in no longer than a month had a job in New York City working for KPMG. So if she got a job straight out of college in the city her resume must have been formatted right and well written.
Then once I got to college in one of my classes last year we were asked to put together a resume and mine was already finished and my teacher told me it was good and just had some minor mistakes. However though every teacher has their own way of telling you how to put together a resume. Some teachers will tell you only one page and others more than one. I believe the number of pages doesn't matter and its the information that you are providing in your resume that matters the most. It shouldn't matter how long your resume is technically if it is longer that means you have had more experience with jobs.
With resumes you should also be constantly adding information to them and keeping them up to date. For example when I go to write this resume for our class I will have to add my work experience that I had from over the summer in New York City. Resumes are an important factor when it comes to looking for jobs and you want to make sure they look as professional as possible.