Dear XXX,
How are you? It has been a long time since we last wrote to each other.
Congratulations for graduating from university! You must have had a great time after graduation. Did you go on vacation overseas? Or have you started looking for a job already?
I am doing fine in school. I am busy, as usual, but I feel that my results have made some progress and I am very satisfied. I will put in even more effort so that I will do well for the upcoming exams.
Do come and visit whenever you are free. Just give me a call. Hope to see you soon!
Yours sincerely,
XXX