Dear Bhakta,
Some more inputs, these may be of help to you
I believe, Trying too hard with the mind to retain Sai baba in it, is unnatural way.
A devotee must have experienced that at some stage in his life, his mind must have easily & joyfully contemplated on Sai baba, without effort. This is the natural way.
Lord Krishna has assured in the Gita that, being in the sattwic mode, one's mind easily gets merged in his object of choice & becomes happy & full in knowledge.
Our body is made up of 7 dhaatus (elements such as bone, flesh, blood etc.) & our food gets converted into the elements. Hence the sattwic food will transform the body & mind. Ofcourse it will take some time & patience to complete the transformation & hence the meditation.
Om Sai Ram