Over the years, I've done a few dovetails and really enjoy the process. I have tried tails first and pins first. They both work but I eventually settled on tails first.
My first step is to mark out the tails. I use a knife and follow it up with a pencil so I can see the lines better. I always mark out waste because I HAVE cut out the wrong pieces before and it is very frustrating.
Over the years, I have gotten better with dovetails. While I can't fit the joint together right from the saw, I only need to do minimal parring with my chisel nowadays.
I slowly worked around the case until all the dovetails are done and dry fitted the case so I have an idea of the look and size of the finished piece.
Once the carcass is fitted, I mark for the interior shelves and start cutting out stopped dado's for the shelves. I get to use one of my favorite planes - the router plane.
I have 3 sizes but I like the medium router plane (Veritas) as it gives me lots of flexibility for the blades using the same blades as the large router plane yet still giving me good control so that I can stop without blowing out the end of the dado (remember, stopped dado's). The process is slow and gradual work and I have 2 interior shelves and 4 sides each. I'll be at this for a while.