Hello (имя твоего друга)!
Thanks for your letter, I liked it! Please send me some pictures of your city and I will send you mine.
Do you like winter? I'm not, because here is always snowy and cold in winter.
I want to come to you in the holidays. We can visit (название ТРЦ какого нибудь). We can go shopping, go to the cinema or just go to the caffe.
I hope we will meet soon,
(Твое имя)
P.S. Соблюдай абзацы, если вас учитель парит по правилам составления писем.