Dear [insert your friend's name],
I hope you're doing well. It has been a long time since the last time I saw you. A lot has happened to say the least. I got a puppy! Her name is Lulu and she is the cutest thing I've ever seen. I also crossed something off my bucket list -- skydiving. I went skydiving in New Zealand and it was the best feeling ever. The adrenaline rush was amazing. You should definitely go skydiving sometime. Write back when you can.
Yours truly,
[insert your name]