Presence gets sold as a state you achieve and then hold, like a handstand. It isn't. It's a return, performed several hundred times a day, mostly badly.
You've had the experience of reading half a page and realizing nothing went in. That gap is normal. The skill isn't preventing it — it's noticing it happened and coming back without a running commentary about how bad you are at this.
Gratitude works the same way. Not a mood you install. A place you keep returning to.
So: you're here now. Look at one thing in the room properly. Then let your mind wander off again, which it will.