All the dimensions of all my halls and rooms must be odd numbered. This way there is a definite center and central line. I flail helplessly when I can't design my forts this way.
I also prefer a central staircase.
I always, always divide my food stockpiles evenly into one for drinks and one for foods. Seeds go in a separate stockpile next to the farms. Farms are always in 3x5 pots or, recently, divided into 5 1x3 plots so I can grow all the plants available from mods. I almost always make 3 or 4 of these plots in one room.
I always make separate levels for each of the major crafts, from top to bottom; farming, woods, crafts, masonry, metalworking. Then I usually make either 1 or 2 more for living areas or mix the living areas for the dwarves into those of their respective crafts.
I prefer to dig a long 5-wide hall leading to a 11x11 room for the trade depot.
I almost never make any above ground structures unless I plan to make a sealed off area for a bunker, in which will dwell my lever pullers/others that I want to survive absolutely any invasion.
AlsoAlsoAlso, I Insist on naming my starting 7 the same every time, and bringing 3 female and 1 male of dogs and horses and one male cat (then killing every single other cat unless I have a nefarious plan for them.)