Internal job searches are not very different from external searches. To be a successful applicant for any job you must present yourself in the best possible light. In essence you are "marketing" yourself as the right candidate for the position.
Resumes and Cover Letters
Resumes and cover letters tell a potential employer a great deal about you. A well-written resume can help you make the right first impression and land you an interview. Including a cover letter gives you an extra opportunity to promote your candidacy.