Talk about how their role may have been small, but very important to the story, and how you appreciated the work they put into bringing the character to life.
Tell them that even from that small role, you feel they have something special, and you predict great things for them in the future!
Elaborate on those.

I always struggle with writing to lesser known actors as well!

Ok, so I'm new to autograph collecting and I was wanting to collect all, or as many as possible, Harry Potter actors. I am just struggling to write to the people who had very minor roles. I mean, some people I want to write to hardly do anything but I really want their autograph so that I can have a collection of harry potter actors. For example I want to write to Louis Doyle who played ernie macmillan in two of the films. Could someone help me by giving me some tips or maybe showing be an example of what they would write or what they have done in that situation :lol: :D