There is no one-way to write a resume. A resume is an individualized marketing tool that is a testimonial of your results and accomplishments. You may even need to have different resumes for different positions that you are applying for.
-Think about the type(s) of jobs/positions that you are interested in pursuing.
-Think about any relevant experience that you may have as it pertains to the position(s) that you are applying for.
-Relevant experience can be internships, assistantships, paid/unpaid work, field experiences, or even volunteer work.
-Think about "targeting" your resume as much as possible. By "targeting" your resume to the type(s) of jobs/positions you are applying for, you can increase your marketability.
-Think about looking at the resume from the "readers" point of view rather than the "writers" point of view. In other words, think about what the employer (reader) would be most interested in knowing about you.
-Think about being thorough and detailed on the resume but don't write a dissertation. Be brief but concise. Be proud of your accomplishments but don't brag about them. Use the "jargon" of the appropriate career field(s) but don't become verbose.