If you want to know what to do with your attention, use it to watch your ego and the present moment. Your attention will resist this kind of focus, but nothing else really matters. Most of what you pay attention to is a way of entertaining yourself. If you pay attention to your ego, you will see how everything you do is geared toward augmenting your sense of self.
Most of our interactions with other people revolve around our egos. As we deal with people, we are secretly trying to prove that we are really wonderful or, at least, not awful. This is how our ego insinuates itself into everything we do. Paying attention to the present is like an antidote to our ego. The ego still plays along and butts in, but, if we focus on what we are doing in each moment, there is not as much room for the ego.
To focus on the present and watch your ego at the same time, just pay attention to your thoughts. If you are focused on what you are doing, you won’t notice your thoughts so much. When you start to notice your thoughts, you can see your ego at work.
To be present in a conversation, you listen and then speak. When the other person is speaking, you just listen. If you are listening to what the other person is saying and thinking of what you want to say back, that is your ego butting in.
If you are worrying about the future, or worrying about the past, that is your ego building itself up. The ego is what holds on to the past and projects itself into the future. Your ego thinks of ways that it will be hurt, or has been hurt, and it alerts you to this danger with worry. In the present, there is just your awareness of what is happening. If you watch for your ego and for the present moment, eventually your ego will contract and the present will expand. Someday you may only have the present. Until then, pay attention to both.