For each internship or job, include the name of the organization where you were employed, the city and state, the title of the positions held, the employment period for each job (include both months and years), and a short description of your accomplishments and technical skills used, listed in 3-4 max bullet points.
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.