Not really, nope. You should not focus on anything. You should experience the experience openly. If you eat a fruit and it reminds you of home, you should experience the food and the memory and yourself, without blocking any of that by focussing on something specifically.
Of course to get to that state of mind you first need to learn by naively focussing on it, that there is more to the experience than what you can see at first. But that is like the additional wheels you put on a child's bike. It's supposed to be on there forever. It's just to get you started.
The goal is to oepn yourself to parts of the experience you didn't have before. For instance have you realized how much your body is automatically communicating your inner feelings through body language? Just keep thinking about your shoulders over the day and see how often they are actually raised as an unconcious way of protecting yourself. It can even happen when you brush your teeth because of what you are thinking about in that moment.
So when you are able to combine all these observations, and are able to not overwrite your observations by thinking too much, and be able to do it all the time without needing to expend any kind of energy on it, then you have achieved Mindfulness.
Even the guys in the text books that are praised so much probably haven't achieved it btw. They themselves would not even claim so. But the people who wrote the books were on a lower level where they thought they needed to expend energy to achieve something, e.g. by telling a more enhanced version of the story they might advertise the book or its philosophy to you.