Hel on writing a friend a letter, maximum points?

I told my friend I was gonna write her a letter, she's a very cool friend but i don't know how to start it. If you can just start writing somethhing nice than ill be able to finish it. Just something you would tell a close friend and how much they mean to you. I'm usually good at writing love letters but I don't wanna make her think I'm in love with her. Please help me start it off and I'll give you as muc points possible. Please and thank you.