The "How fortunate you are" reflection is simply to reflect on how fortunate you are. That's it. Stop. The minute the mind goes off into stories about other people,. No. Wrong. note it, come back. It's that simple. Note it, come back. We're going to stick with why we're fortunate. e.g. we have a lot of money, we're fortunate. In the back of our mind we know, yes, there's people with less money, but we're not going to get into that story; we're not going to go into their suffering. That's for a different meditation subject, that's for Compassionate/Lovingkindness meditation. That's not for "How fortunate we are".
"How fortunate we are" is just to look right here at how many different ways we are fortunate. That's it, then stop. The minute the mind's off: we note that we're lost, we come back; we note that we're lost, we come back.
It's very similar to the reflection on good Kamma, or Sympathetic Joy, in that the word "but" and all of its relatives, such as "maybe", "perhaps", "could be" - we have to get those words out of the meditation, because they're not part of it. The minute they come in strongly, we're lost, and we're doing Dukkha meditation instead of "how fortunate we are" meditation.
The purpose of reflecting on "how fortunate we are" is to give us joy, give us contentment: because "Yes, we have so much". Then later you could change into Compassion/Lovingkindness meditation, a different reflection where there's other people who don't have as much, and we wish they could have more, too, we wish they could be like us. That's Compassionate/Lovingkindness. So be sure to keep the different reflections separate. If you're having difficulties with keeping the reflections separate - you start with one, you go into another, that's normal. It's just restlessness, wandering mind. As soon as you're lost: note it; come back, start again.