If the adhesive becomes hard to cut, it has most likely cooled down. Use your iOpener or heat gun for 1-2 minutes to reheat it.

When you slice near the front facing camera, insert only the tip of the opening pick (~2.5 mm) to avoid damaging or smearing the camera.

Insert a fourth opening pick at the top left corner of the screen.

Slide the opening pick along the top edge of the phone to slice the adhesive.

Leave the opening pick in the top right corner to prevent the adhesive from resealing.