Here is how I make a dovetail box.
Layout and cut boards.
I use a plane to "shoot" boards perfectly square. I make sure all pairs (ends and sides) are true and square.
I set my cutting gauge to a hair wider than the boards thickness and scribe all way round ends of all boards.
Lay out my dovetails by eye with a set of dividers to keep them even. I set out the tails and cut them clamping the long sides together. I cut both boards at the same time this way with back saw and coping saw.
Lay out bottom dado groove to width of my dado plane blade.
Start end of grooves short of end of boards so they won't show on outside.
Cutting groove with dado plane.
Lay out pins from tails. I like to mark waste areas so I don't get confused.
Cut out pins with back saw and coping saw. Make sure to cut on correct side of line!
Trim to scribed line cutting in from both sides.
Pare up true.
All pieces cut and ready to fit up.
Trim pins as needed.
Fit up tight but not too tight especially on outside pins or boards may split.
Nothing to it! Now for the bottom and lid.
