Think of a resume as “self-advertisement” that sums up your experience on one page. Your resume is one of the most important pieces of your job application. It gives the hiring manager an overview of the qualifications you have for the job for which you’re applying. You should also familiarize yourself with the difference between a resume and a cover letter.
In the short term, you should tweak your resume based on each job you apply to. For example, if one position you’re applying to seems to weigh a certain responsibility or focus over another, you should be sure your resume conveys your expertise in this area. At the same time, you should be updating your resume with your experience as it develops, adding any new skills you’ve learned, courses you’ve taken or awards you won.