Hello!
I'm new, but I thought I'd share this. I've been collecting Football/Soccer autographs for one year, and it's the best thing you can do.

How to get autographs?
You basically either email them, and ask for an autograph with a nice text and you put your address in the text so they can send it back.
If you want Chelsea players, or Manchester United players autograph you would have to send a letter requesting autographs, and photos you want signed. And in the enovlope, you need to put a SASE (Self-Addressed, Stamped Envelope) with your address so they can send the photos back with an autograph.

Personal success
So far I've got many autographs, like RVP, Luke Shaw, Toni Kroos, Zlatan, Mourinho, Hazard, Neymar Beckenbauer and many many more.

You can check out photos on my Facebook page, and I update it daily
https://www.facebook.com/RidMosAutos?fref=nf

I'd be happy to help you get started, and give you a few addresses and emails to send to.
You will love it.