Need tips for removing iPad digitizer

I’m trying to replace my cracked iPad screen, but am having a very hard time melting the glue and prying the thing open. I tried to use the iOpener that came with my replacement kit, but after about an hour I still can’t lift the screen to stick the guitar pick in. And so far all I’ve done is make the cracks worse. I was hoping to find some tips or tricks to facilitate or expedite the process. Maybe I’m just being impatient, but I figured it couldn’t hurt to ask.