Here five things job seekers should leave off their resumes:
1. An objective
I've never seen an objective that made a candidate more appealing, and often they're downright horrible. They usually fall in one of three categories: (1) objectives that are all about what you want ("a position that allows me to develop my interest in international relations"), which is at odds with what this stage of the hiring process is all about (what the company wants), (2) objectives that aren't tailored enough to the position or even have nothing to do with it (which makes it look like you're blasting your resume out without enough of a focus), or (3) objectives that simply don't add anything compelling (and therefore just waste space). The resume is about showing your experience, skills, and accomplishments. If you want to talk about how this particular position is the perfect next step in your career, use the cover letter for that.
2. Any mention of references, including a statement that "references are available upon request"
This goes unsaid; no one assumes that references could possibly not be available. You're not causing any harm to have it on there, but it's a waste of space that you could use for something else (including some refreshing white space). The exception to this is if you have a particularly impressive reference (such as a local politician, head of a Fortune 500 company, or someone personally acquainted with the person reviewing your resume).
3. Any mention of high school
I don't care which high school you attended or how accomplished you were there. If you're more than a few years past your high school graduation date, no mention of high school belongs on your resume. Move on!
4. Extra documentation
Unless the company has specifically asked for something other than a cover letter and resume, don't send it. Candidates sometimes include writing samples, letters of recommendation, transcripts, even photos on occasion. Bring these sorts of extras (well, not photos) to your interview or wait to see if you're asked for this sort of extra documentation, but don't send it preemptively. In most cases, it won't help you, and in some cases it can actually hurt -- for instance, when a candidate attaches an unsolicited 20-page writing sample, it looks naive and makes me think he or she doesn't understand the hiring process.
5. A third page
If you're in your 20s, your resume should only be one page; there's not enough experience to justify a second one. After that, two pages are fine, but you go over that limit at your own peril. Hiring managers may be only spending 20 or 30 seconds on your application initially, so extra pages either (a) are ignored or (b) dilute the impact of the others. Yes, you have much impressive experience, but the resume is for highlights. Cut that thing in half.