how does one write a love letter?

well...im graduating soon...and i dont want to leave without saying anything to her..but considering my classmates knowing about my infatuation over her..i decided to take a discreet approach which would be a letter...in all honesty, i really do want to say it personally...but with everything as a consequence plus scandal...might as well take a quiet approach to it...i know its a losing battle but i still want to do it coz....i dont know...i just really want her to know..that's it, i suppose...