It can be helpful to use a knotted cord or string of beads too. Each time you inhale and exhale, focus on passing one bead or knot through your fingers. Doing this on a strand or cord gives your mind a tangible bit of progress, but over time it also helps with the purpose of meditation – the strand or cord reverses and you begin again, renewing the calm and stillness in your mind.
What I mean by that is I just don’t worry about it. If I lose focus that’s ok. It has always seemed to me that “focus” is not a helpful way to think about it anyway. It’s more just being present and aware without stress or rumination.
So when I find myself getting frustrated, I just remind myself that simply taking the time to sit with no distractions is already a success. There is really no such thing as a “bad” meditation session – and then I relax and give my mental self a little pat on the head and just count my breaths for a while.
If my thoughts start taking me away I just take a deep breath and reset to my presence