The next section of your application letter should describe what you have to offer the employer.
Remember, you are interpreting your resume, not repeating it.
Mention specifically how your qualifications match the job you are applying for. In this portion of the letter, make your case for your candidacy.
Use specific examples whenever possible. For example, if you say that you have lots of experience working successfully on team projects, provide an example of a time you worked in a group and achieved success.