Rachel Said:

My neighbor has asked me to write a college recommendation letter for her son.Any suggestions on what to write?

We Answered:

"Every recommendation letter should include three key components:

A paragraph or sentence that explains how you know this person and the duration of your relationship with them.
An evaluation of the person and their skills/accomplishments. If possible offer specific examples that illustrate the person’s strengths and qualifications.
A summary that explains why you would recommend this person and to what degree you would recommend them."

There are other pointers and examples on the site linked below. :)
Hope that helps!