For glitch #1, when you jump from the balcony ledge to the window sill, you must time your jump perfect. And when you are on the next window sill, you must jump around the corner and crouch in the air to get in the stairs.
For glitch #2, you must jump and crouch in the air and move forward, old school mode must be on.
For glitch #3, you must jump in the air and crouch in the air while moving forward to get on that ledge.
