Well the techniques I originally learned through Aikido was what is often referred to as breathing meditation but it wasn't until I went to Japan that I experienced Kototama meditation (roughly described aas the use of mantra).
I also tried visualisation meditation which is very good for focusing the imagination. I find it easiest after I have relaxed my body with breathing techniques and then, much like a daydream, I visualise a building. Each time i return to this building inside and out room by room and it enables me to shed any worrisome thoughts that might be keeping me tense and awake.
Moving on to Christian mysticism: I have experienced the benefits of prayer, silent refletion (or listening with the heart) and lectio.
Put very briefly:
Meditation through prayer is a way of enngaging the body, mind and spirit in unison by repeating a phrase physically, bringing the mind back to its meaning and your intentions when it strays, and listening for movements in the depth of your being.
Silent reflection is a phenomenon by which you enter a retreat or sanctury and you seperate yourself from the busy-ness of the world. It can bery extremely distressing as you de-tox but after a day or so your senses open and you find yourself again, without the noise and distraction. You also become much more aware of the beauty of the world.
lectio is a way of reading that involves taking the time to exlplore the meaning of each word and phrase in its entirety. With a bit of practice it really sharpens the mind.
But I admit to being very much the novice at the above.
The techniques both Christian and non christian overlap all the time: many people maintain the distinction between Xtian and Buddhist is that while the latter seeks to empty the mind and the Xtian one seeks to fill the mind with thoughts relating to scripture howeverI would say that this is only partly true. Much of the aim of the christian mystical tradition is to listen to what our souls are trying to tell us.
en.wikipedia.org/wiki/Christian_meditati...._Ignatius_of_Loyola