My experience:

* remove the SIM tray first before starting

* pull hard to open the iPhone with the suction cup, make sure you hold the other side as you need to disconnect the first three cables before fully removing the display

* when disconnecting the cables, take your time, they give a 'click' when they're disconnected

* cable 3 is a pain to slide back in, do this by wiggling the display a bit

* take care when sliding the logic board back in: do not push too hard or the camera will be disconnected from the logic board at the bottom

* the hair dryer hint actually works!