Putting aside everything, not allowing anything else to enter your mind, in total earnestness remain with all the strength you have focused on the 'I am'. Persist on this focus or meditation on the 'I am' till you drive it away into oblivion. If your effort is sincere and earnest enough the 'I am' is bound to disappear, for that is its nemesis. Then whatever remains is your True being or Self, call it Eternity, the Absolute or 'Parabrahman'.