You are competing against so many other applicants and you know none of them, so it is natural to feel that you need any edge available. Because of this, you may feel a need to provide every single detail of your life, exploiting your resume in particular to do so. While we, of course, want you to make the most of your opportunities, we also want to be sure that you are not entering into a situation in which you are offering so much that you are experiencing diminishing returns.
With respect to your resume, it may be painful, but many resumes - especially those where every margin is stretched and every font is shrunken - offer too much information. Some resumes become so dense with text that instead of being easily scanable, which is your objective, they become entirely impenetrable and easy to ignore. We often tell our candidates that less is more and that they benefit when they provide a brief resume which the reader will read in full, rather than a dense resume which he/she will not read at all. Recently, at the Association of International Graduate Consultants Conference, eight leading admissions officers were asked whether they would prefer a one page or two page resume and one led all of the others, stating, Everyone together... one page!
But, even with a one page resume, you need to understand what to include and what to exclude and the answer to this riddle is different for everyone. You may consider jettisoning internships from years gone by, for example, or reducing the number of bullets offered in past jobs. Maybe you will eliminate entries for community involvements from many years gone by. Your agenda with your resume should be to create maximum impact and sometimes that can occur through fewer words and bullets. You may need to make tough choices, but it will be worth it if you are submitting a stronger resume and thus making a stronger statement about yourself.