How could i write a letter to principal (college)

the purpos of the letter is to inform the principal of the good and bad things of the college

[Stilo]

Dear Sir/Madam

I am aware of the constraints on your time but I would like to bring the following points to your attention.......

I think........ good points

There are, however some points that I would wish to make that may improve the college....... bad points

Yours sincerley