Sending Requests To Other Countries...

[GUN5L1N6ER]

I know this has probably been asked in another post, but I couldn't find it. So, here goes. I have recently starting collecting after a loooonnnggg hiatus and I have really enjoyed sending requests, waiting, and seeing what happens when the envelopes arrives and I open it. However, there are numerous celebrities and people of interest that reside in England, Germany, Canada, and various other places. I have never attempted to send anything to another country. I live in the states and I have tons of questions, but the most important ones are these:
1. What type of postage do I need or rather how do I make sure the envelope comes back to me?
2. Do I need to use extra precautions in packaging?
3. When sending overseas what is the "average" turnaround time?
I look forward to everyone's responses, but for now, I'm out of space!