Your resume is one of the first documents your potential employer's see about you, so it's important that you make it professional, informative, and appropriate to the job your applying for.
There are multiple types of resumes you can write, deepening on whether you want to highlight your work history, your skills set, a combination of work history and skills, etc. Many times you will want to write a resume that is targeted, meaning it is written to address the specific skills and qualifications discussed in the job posting. For more information on the different types of resumes, check out Resume Types: Chronological, Functional, Combined, Targeted.
Your cover letter provides your potential future employers with their first impression of you as a candidate so it's important that you write a well thought-out cover letter that entices your potential employer to look at your resume.
It's critical that you tailor your cover letter to the position you are applying for and explaining why you would be a good fit for the position. Cover letters should be personal and inviting, demonstrating what you can bring to the company and position.