Today's job search process has little face-to-face contact in the early stages. Whatever you put on paper could ultimately make or break your chances of getting an interview. That's why the resume is a crucial document, and every space counts. While you typically want to keep your information to one page, you also should make sure that all of your credentials and talents are properly stated.
First, make sure you're modifying your resume for every job you're applying for. Hiring managers can tell when they receive a generic cover letter or resume, and when they do, those are the first to get tossed aside. Certain keywords will likely stand out to the recruiter, and to ensure you make it past the first round, you should include them organically across the page.
Above all things, your work experience should be clearly stated. Whether you have a dozen of part-time jobs, volunteer experience and practicum placements under your belt or just a few, make sure you highlight the accomplishments you achieved at each in a concise and easy-to-read summary.