Not too bad for a first serious fortress. I am sure you will soon have plenty of Fun.
My overall design suggestion goes something like this.
3x5 entrance, or 5x3, whichever is a more pleasant hillside I will stick with XxY for the rest of the description though.
Put some traps in there and a 3x1 drawbridge in the middle.
Then a 7x7 area for the depot.
Follow that up with a 3x10 hallway. Again some traps and a drawbridge, they should be on the depot side.
Off that 3x10 hallway carve a barracks area 9x9 with a 2x3 entranceway. The entrance for it should be past the inner drawbridge.
Everything else can grow organically. Other then the entrance you have I think your doing great.
I tend to plop mason and mechanic shops directly in the area of the stones I need to use up. Then I remove the workshops when the region is cleared. No hauling except for finished products.
I have masons make a lot of blocks for training; and will generally enable the masonry skill for all my haulers, then use the workshop profile to require a minimum skill of proficient. This lets the haulers be the ones building the walls and floors that use up the blocks. New workshops go up as I expand, get set for the proper masons, and then the masons are moved to the new area, and haulers spend time building with the blocks from the old area.
Mechanisms generally end up being dumped if they are below a certain quality. It is important to have a good item destroying refuse area, either a magma vent/reservoir or an atom smasher.