Why can't I slide my foot up?! Help! It been weeks I still can't ollie! ?

Nothing to do with the shoes. You have to slide your foot at an angle, try it out not moving. Hold the end down with your foot and slide your foot in different positions and it when you see you can move your foot do that position. Um i dunno how the other guys do the ollie but in all the vids i saw and the way i do it you start jumping when you crouch.. just that the back foot is hitting the tail while your jumping with the middle foot first making the board go like / so you can slide it in the air and make it go like -.