I draft new immigrants with martial skills into the military. I usually end up with several squads, separated into male and female groups. I nickname the males "vikings" and the females "amazons" for ease of reference. I keep them apart because I don't want them getting married (which happens a lot to soldiers in close proximity with one another). The female soldiers tend to carry their babies with them into battle with distressing regularity, so I tend to use them only for duty inside the fortress itself.
The non-hunter and non-miner civilians, I also draft into military squads, but for the most part, let them continue on working regular jobs. With training turned off in the military schedule menu, they train individually in their assigned barracks whenever they have nothing else to do, so I never have any idle dwarves.
I also enable all jobs for everyone, and let them work on everything. Once someone hits a high level of skill in a profession (master or better), they get their own workshop/bedroom/dining room unit. Until then, everyone sleeps in one large room (though each bed is set to be a 1x1 bedroom).
The miners and hunters don't work well with the military for some reason. I organize the miners into their own squad with no weapon assigned (they'll sometimes use the picks they're carrying if activated, but it's not reliable). Hunters annoy me because they leave bolts scattered all around the map, so I don't use them.
So other than the few specialized crafters, I don't really pay attention much to what an individual dwarf is up to. I tend to order all crafting through the manager screen.