An ability to go within comes with the practice of interiorisation. What one has to do is to fix a suitable time and place for regular concentration. Of course it need not be rigid but it certainly helps since when we fix a time and place the forces of nature within and without are in a receptive state. A little quiet corner with an atmosphere of Her Presence through Her photograph, music, incense could be created. The seat should be neither too hard as to make one uncomfortable nor too soft to make one feel sleepy. For the same reasons a state of hunger or a state of having eaten too much are not advisable.
One could start the process by taking the help of thought or idea that breathes of divinity, a phrase or a mantra to start the inner connection. One could read Savitri or Her prayer to enter such a state gradually. Then one starts going within by concentrating upon Her Name or Image in the center of the chest (heart centre) or the head (anywhere on the crown area). Practice initially for the minutes bringing the mind back from its wanderings. Do it twice a day and later increase the time to 20 minutes and if possible thrice a day.
Persist despite resistance or absence of immediate result. To truly succeed one has to do it as an act of love or with a heart with sincere aspiration. This is possible only if one loves the goal. The practice of equanimity and niskama karma (desireless action) is a great help to prepare the ground.