I don't worry about being here "now." Whatever is on my mind is here now, whether I am thinking only about what I am typing now, or bringing the past into the present moment, or bringing the future into the present moment. Everything is now. In fact everything is always just this.
It seems to me that when people talk about having trouble being in the now, they are really talking about intrusive thoughts, a racing mind bringing in thoughts about the past or the future. In effect, worry. It is a form of anxiety. I used to have that problem, but I don't any more.
I would advise not to try and directly stop the racing mind. Directly stopping the racing mind is impossible because the racing mind is a result, a symptom of unresolved issues. To stop the racing mind the issues need to be resolved. In other words, the stopping of the racing mind is an indirect result of resolving issues.
What I am trying to point out is that you can spend years trying to stop or control a racing mind and only succeed in wasting a lot of time. The racing thoughts problem isn't going to be stopped by force of will. It is only going to stop when the cause is removed.
In my case I was not looking to stop my racing mind. I was looking to resolve the inordinate mental anguish I was immersed in. At one point I even became aware that my mind was racing because I was trying to outrun my pain - trying to think my way out of it.
If there is an enormous amount of pain, and you try and rationalize your way out of it, your mind is going to race. The racing thoughts are are trying to outrun pain, they are screaming, "You need to resolve this!" Not doing so results in anxiety.
You see, the reality is, you experienced pain, or mental anguish, and somehow you did not fully experience it. It got repressed. You have unfinished business. On a personal level, to get back in touch with reality, the unexperienced pain needs to be felt. It needs to be felt to put you back in touch with your personal reality.
Now, I am all about getting to Impersonal Consciousness or Awareness. But it is going to be difficult to get there, if you have a ton of personal stuff in the way. Consciousness wants to experience everything, and if you have unfelt pain, it is going to insist that you feel it. Consciousness isn't going to avoid anything. It will not let you off the hook.
In my case, I went to a therapist who did Gestalt work. It was done in a group. I primarily worked on my dreams because they spoke the truth of what was going on in me. And what the dreams were symbolizing over and over was the pain.
When I did break through into the pain, it was enormous, and it was terrifying, and yet the experiencing of it allowed it to leave. At first it seemed bottomless, but eventually it cleared itself out. This did take a few years.
What happened when the pain was experienced and let go of? There was nothing left to try and outrun with my mind. I didn't have to try and rationalize my way around it. The result was a quiet mind.
Since then my mind has been extremely quiet. It thinks, but very little, and it doesn't have thoughts coming in unwanted, or having some other agenda, other than whatever task I am presently doing.
At work, whatever I am working on is all that is going on. Away from work, most of my leisure is spent on thinking about, or experiencing non-duality. It is what I want to think about. It is what I am. There are no intrusive thoughts.
If you really want to look at the issue of repressed pain and its relation to a racing, anxious, mind, read the book "The Primal Scream" by Arthur Janov. It made a difference for me.