If you're applying to work at a startup, particularly if you're applying for a junior or internship position, you'd do well to read Justin Kan's article about what to put on your CV:
Overall, startups are looking for employees who are exceptional in the one key thing that they will be doing, whether it is scaling the backend system or doing the visual design. In your resume you need to 1) demonstrate that you are exceptional at the thing you do, and 2) not be disqualified by seeming crazy or imbalanced. A simple rule: if something on your resume isn't achieving one of the aforementioned two things, leave it off.
Having reviewed numerous CVs in the past, I can't agree more. Another point I'd add is that, if you're applying for a junior position and do not have significant work experience (summer jobs in fields that are completely orthogonal, e.g. retail, do not count), then make sure you mention those hobby projects which can actually give your CV some value. All too often, I see CVs where, for example, the applicant will mention that they are highly proficient in PHP or Ruby but there'll be no mention of what they actually did to become proficient. "I built an stargazing GPS-enabled app in my spare time" should definitely appear on your CV, no matter how rudimentary the app may be or whether it is "serious".
Large companies may not care about such "icebergs" of experience, but startups definitely will.
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