-hs: name, location, and only significant awards (beyond this, no one really cares)
-undergrad: name, location, awards, extracurrics, gpa (not a must), degree info
-work experience (any regardless of ft/pt/summer) where and what you did and for how long you did it
-skills (if any)
keep it to one page, pay attention to spacing (and spelling/grammar errors of course)
if you don't have much else to add, don't try to add info that will only make the reader respond with a "so? who cares?"
stay away from resume fluff!
and make sure that the information is easily readable and accessible.
hope that helps.