The letter S

I started today with Mike Wilks' 1000 pieces jigsaw puzzle The Ultimate Alphabet: The Letter S.
We have a spare desk in a room on the top floor. After I cleaned the desktop I had enough space to lay the puzzle and leave it in my breaks.
As you can see I started with the borders. I couldn't find two pieces yet, but I am sure I will later.
For larger puzzles this has proven to me to be the best approach. Does someone have a different approach?