Try to find your centre, right now. Is it in the head, or somewhere in the stomach or chest? Where, exactly? Look directly into the supposed central "me-ness," then look for the centre of that.
Close your eyes, and try to find what shape you are. Where do you end? Open your eyes, and do the same. Where does what you call "you" end, and the "other" begin? What about the point where they meet, who is there at that place?
Gaze into your eyes in the mirror. Who is seeing what, and what is the awareness that contains it all?
Find the most real thing in your experience, right now. What's the most stable, solid, and reliable "thing" where you are right now?
Look into that troublesome loop of thoughts and feelings, and see if there's anyone being tossed around in there. Notice that you are the sky, in which the maelstrom or the peaceful weather can occur.
Stop a moment and see the show, as the show. Thoughts, feelings, notions of self-hood or non-selfhood all appear and disappear. You don't.