There’s no need for any special concentration in order to say the Jesus Prayer.
It doesn’t require any effort if you have love of God. Wherever you are, on a stool, a chair, in a car, anywhere, on the road, at school, in the office, at work, you can say the prayer: ‘Lord Jesus Christ have mercy upon me’.
Gently, without pressure, without pushing.
Saint Porphyrios of Kavsokalyvia