2 

  O.K. Now the second tree is removed I have put a hose down to mark the shape of the pond then removed the turf.

Mistake 1. I piled the old turf under where I was going to stack the removed soil. When I wanted to move some of the soil I had difficulty digging into it.

Mistake 2.The top left corner is a bit more acute than I would have liked it to be. Later proved to be slightly out of keeping with the pond's natural look.