I ran the panel through the thickness planer down to almost 1/2 inch, then I ran it through the drum sander to clean up milling marks. I also ran the shelves through the drum sander to even out any differences from the glue up and to remove any milling marks.
The rails and stiles each have a 1/4 inch groove 1/2 inch deep, tenons were cut on the stiles and bridle joints were cut in the rails. I dry fit the door to check the fit of all the joints. After dropping in 1/4 inch spacer balls to hold the door but still allow for movement, I applied glue to the tenons and shoulders but not the panel and clamped it up.
After removing the clamps from the door I trim it to fit. When I make inset doors I build them to the size of the opening then trim them to fit. Once the door is sized correctly I use thin shims so center the door in the opening to check the fit and size. Only now will I mark the locations of the hinges and mortise the area for the hinge to sit flush on the door. There are many methods to mortise for a hinge but I prefer to mark the hinge with a sharp knife and remove the waste with a chisel.
With the hinges installed on the door I use two-sided tape and the same shims to align the door. If you are lucky and you hold the door carefully you can open the door while keeping the cabinet side of the hinges attached. But I you aren't that lucky you'll call your neighbor and have him hold the door while you align the hinges like I did. You'll notice in the picture that I had also installed the door pull by this time, one all the hardware was fitted and the swing of the door checked I was ready to take everything apart and give it a final sanding.