Ahem.... I guess I should have searched the forum archives for an answer to my question about mantras
I just did and found the following answer posted before by Michael on the subject of mantras:
"The mantra based meditation technique 'Discover Meditation' will work just fine if you choose your own mantra.
I would suggest you pick a mantra that sounds soothing to you.
If the first sound you select is later felt to be unsuitable, I encourage you to then choose or create another mantra until you find something that resonates with you.
Regarding your comment:
"Could I use longer mantras like full sentences or rows of letters to make it more challenging and to require sharper concentration"
To get the greatest success with my course, I encourage you to choose a simple mantra and avoid complex sentences.
When you listen to Discover Meditation, you will hear me talk about not trying so hard... This applies to concentrating on your mantra also.
When you repeat your chosen mantra in your mind it should not be a strained effort to try and keep it as your dominant focus.
When you find your attention has wandered, you should make no effort to return deliberately to your mantra, but just resume its repetition in a passive manner by 'favoring' your mantra over other thoughts.
Please let us all know how you get along.
Michael"