I've been looking around the website for a few days now and finally decided to sign up

Anyway since I stumble across the site I've been thinking about trying to send a letter or two out.
Is it really as easy as it sounds?
I write a short letter saying I'm a fan and asking for an autograph? include a SASE?(I think that's right)
And just wait pretty much? Would it help if I included a photo or does it just depend on who I'm sending it too?
One last question too. Sorry
If I'm hoping to get a picture back how big of an envelope should I included?
Sorry for all the questions.

And I was hoping to send a letter to Evangeline Lilly, if that helps at all.