Your goal should be to write your resume with both robots and humans in mind. Many organizations use Applicant Tracking Systems to sort and vet resumes, before hiring managers ever take a look at them. This means that you could have the best experience and qualifications in a whole field of candidates, and a pretty decent resume besides, but your information will fall through the cracks if your resume doesn’t contain the right keywords. Good keywords will refer not only to your experience but to the job description in the posting as well.
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.