Listening to a lecture of Guru Siyag before starting meditation seems to work quite well.

Last night’s meditation was a wonderful samadhi. Today, I am fighting with some memories of my room-mate laughing at a TV show. For some reason, the memory of her laughter echoes over and over in my head. It is competing for time with my japa jap. Perhaps if I had not started the japa jap, it would never have come up as an issue?

Also note that supposedly Theravada Buddhism has the solution for people like me who crave samadhi – the buddha came up with insight meditation because he noted that even samadhi states were temporary.