The crumpled notepaper effect on which our wisdom appears was relatively easy to achieve, to wit, we wrote our wisdom on some notepaper and crumpled it up. Getting it onto the background of fallen leaves wasn't so easy, as we wanted to be able to see the leaves through the holes in the notepaper.
That should be easy; just place a background of flat colour behind the notepaper, scan it into the computer, and replace the background colour with transparent. This technique is often used in the film industry and is colloquially known as blue screen.
The first problem we had was that the background colour, which looked fairly flat to the eye, varied too much and no amount of tweaking could get the background fully transparent without also making parts of the notepaper vanish.
We resolved that by placing a flatter, more distinctively coloured piece of card behind the notepaper when it was scanned. Unfortunately, the notepaper was sufficiently thin that this bolder colour bled through, making the notepaper look pink. We didn't resolve that problem, and the end result wasn't exactly what we wanted, but it was good enough. I quite like it now.