A recommendation letters is to "recommend" the student to his/her next school, so please include positive observations and comments only.
Please draft a letter with the following in mind and attach it to the form. Do not complete the form, particularly if it asks on ranking or grades, etc.
First paragraph - introduce the student and how long you have known them
Second Paragraph - Discuss what sets them apart
Third Paragraph - Discuss their academic strengths in your class
Fourth paragraph - Provide the recommendation