What worked and changed everything for me was to begin to stare at a spot on the wall, or at yantra/mandala/kasinas (same kind of things).
the yantra or kasinas work great because of the geometric patterns that makes early progress very easy to see visually.
I teach this technique to friends and family who begin Samadhi.
I believe open eye/stare practice is significantly superior to breath meditation for most people nowadays.
thousands of years ago, our lifestyle was different, we did not have any artificial lights and we weren't constantly distracted by traffic/cars/cellphones/tvs/computers etc...
This made developing our visual and auditive senses a necessity with growing up in a modern society, but sensing a very fainth sensation on the tip of the nose more difficult than it could be.
I believe people were naturally more sensitive to bodily sensations because of that.
But today, we use our eyes constantly and we are not used to silence or distractionless moments, so as soon as we close our eyes for meditation, the mind goes nut and start to freak out.
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Anyway, Staring at the center of a yantra, soon enough (2-10 minutes), the lines in the pictures will start glowing and the perifiral vision will start getting darker, like a tunnel vision.
This is signs that your mind is getting concentrated. Enjoy!
After a few days of practicing this, the tunnel vision will stabilize. this is access concentration.
suggested steps:
1- pick an image you like and print it out or use a phone or tablet at a comfortable distance (whatever feel right for you (2-6 feet))
2- stare at the center of the imagine, think about stuff if you want, it doesn't really matter.
3- do this as often as you can for 10 minutes sessions only with a timer.
4*- make a journal, what happened during this session, how did you feel?
5*- try to only "see". you want to try to only see. isolate that sense from all the other, only see.
** 10 sessions spread throughout the day should be more effective than 10 sessions in a row and nothing for the rest of the day.
Concentration seem to require momentum.
** Shorter sessions are better when you begin since we can get distracted and waste a 30 minutes session daydreaming,
10 minutes sessions are good because they are usually long enough to start to see stuff happening visually, and short enough to not annoy the mind and avoid getting lost in thoughts.