The letting go meditation consists of saying "breath" when you are focused on your breath, and saying "not breath" when you are not focused on it. When I first read this, I thought to myself, "This seems like it will be relatively simple..."
Like all meditation practices, this was equally humbling: I started out saying "breath, breath, breath" but then I got sidetracked by the things I needed to do at work (which then led to non-work related thoughts :). I finished off the meditation by breathing very deeply as a way to stay focused on my breath.
On Day 7, I did the 15 minute body scan meditation. The body scan is very similar to yoga nidra or some savasana practices; however, in the kind depicted by Real Happiness, you are doing this practice on your own.
This required a great more of concentration on my part, as I swapped between focusing on my body, thoughts and breath.