These are all good questions and there is no one answer. Your resume should reflect your education and professional experiences. For college students, relevant classes, volunteer work and activities can all be included in your resume (sometimes needed to get the resume to fill one page). But what about your high school and the writing you did for your high school newspaper? Maybe you played sports since junior high and won some pretty distinguished awards along the way. It's hard to just throw all of that hard work away.
The key to resume writing is relevance. Is this experience relevant to the internship or position I am applying for? Also, high honors and awards are usually a good idea to keep on your resume at least for a period of time. This reflects your dedication and how well you perform. By the time you are a senior in college you might rethink your resume and begin taking your high school experiences off. There are many ways you can pare down your resume, such as: removing some of the experiences, shortening your bullets, removing unnecessary words and articles (a, an, the), and by limiting your resume to experiences relevant to the position you are applying for. If you’ve done all of the above and your resume still goes over by one or two lines you can try changing the margins or change the empty spaces between categories to a smaller font.
On the other hand, if your resume is full of education, relevant experiences, volunteer and community service activities, publications, workshops/training, computer and foreign language skills, etc., you may need to create a two page resume. If your resume does go to more than one page, be sure to put your name and page 2 on the second page and try to fill up at least 3/4's of the second page.
To sum up what we have discussed in this article, a one page resume is ideal if you can include all of the relevant information you need to get across to the employer that you are the best candidate for the job. Your focus when writing your resume should be on the employer and what they would want to know about you. If by doing a one page resume you are leaving out a great deal of information that could determine if you ultimately get the internship or job, then opt for doing a two page resume.