Excellent guide. This is an incredibly frustrating device to take apart and get back together.
Probably the toughest part is the ribbon cables. They're positively tiny and some of them force you to insert them without much space to work. The best strategy I've found is to use a small poking tool like a pen cap clip to nudge them very patiently into place. First one corner in the socket so it doesn't fly back out, then nudge it along and get the other corner. Then straighten it out to line up perfectly. Being extremely patient and gentle are key -- if you even slightly bend a corner without damaging the wires, it becomes infinitely harder to get it in successfully. Most of the ribbons have small notches you can use to help you push them in and judge how far in they are.
Also if the wifi antenna wire gets loose when you're putting it back together, you'll have to undo everything to get it back into the right spot.
Careful when reassembling -- watch the position of the black wifi antenna wire! I got mine most of the way back together and noticed it wouldn't close all the way. This wire had come out of the little posts holding it in place and was wedged between the screen and motherboard. Now I have to take it all apart again to fix this.
Also if you're taking the board out of a working unit to get at the CLK signal to backup the NAND chip ("hardmod"), you don't need to remove the difficult ribbon cable in this step, or the other two wide ones at the top right from earlier. Leave them attached and swing the board out. It won't rotate a full 180 degrees to sit flat outside the unit, but you can open the screen 90 degrees to prop the rest up while having the board out on your table.
Do yourself a favor and DON'T remove the 2.5 mm silver screw (yellow circle). It just holds in a little plastic bit under the volume control. The board comes out just fine with the screw still in. If you remove it, the plastic bit will fall out at random when you turn over the case.
First time I took mine apart, I noticed something fall out later, tracked it down and then puzzled over what it was and where it came from.