My standard procedure:
1. Cut trees for building material, gather plants.
2. Dig ramps and a long 3 tile wide entry/passive defense tunnel in the first soil layer, to the vicinity of a murky pool, with the internal 1x3 main stair shaft at the tunnels end (when caravans use wagons, the trade depot goes near the end of this tunnel too)
3. Dig storage halls one level deeper around the stair shaft to get all goods underground asap, including a walled room for water slightly smaller than the murky pool, while building the trade depot
4. Some ropes in the middle of the entry tunnel for watch animals to keep the thieves out
5. A basic food and booze industry in the food storage. Begin cooking training. I want some valuable roasts ready when the traders arrive.
6. Prepare the underground farm room above the food storage (gets a direct stair connection later); irrigation is done by drilling into the murky pool, excess water is absorbed by the pond at the other end of the farm room. Two farm plots for booze variety.
7. Furniture industry in the wood storage
8. A well, crude barracks with 10 beds (15 tiles away from the workshops to avoid the noise complaints), a small managers/bookkeepers office and a simple dining hall near the food storage. This will keep the morals stable. All in the same soil layer. Digging rooms in rock takes too much time now. And misleads to smoothing and engraving, which takes even more time.
At this point all basic needs are taken care of, the dwarfs are happy, the small settlement can survive on it's own and can be sealed shut for as long as necessary.
9. Drill the main shaft further down, begin mining, set up charcoal/coke production and smelters
10. After the first immigration wave a mechanics workshop and a smithy
11. Set a few lines of cage traps in the entry tunnel
12. Clothing and leather workshops
13. Set up training barracks, get the steel and armaments industry humming and start converting some of the little suckers into bloodthirsty death machines, fill the entry tunnel with serrated steel disc traps.
14. As soon as some dwarfs are armed and dangerous, search for magma sources, as they shorten the metal production chain and thereby drastically increase the output of the smelters. And they greatly reduce the need for wood harvesting too.
From here on everything is open. The fortress is sufficiently safe, the dwarfs are happy, the arms industry runs like a clockwork and fills my storages with equipment of ever improving quality, up to the point where I can afford to sell everything that is not a masterwork. More and more dwarfs will reach champion level. Time to have fun with whatever is stupid enough to approximate the fortress. And to build sphinxes left and right beside the fortress entrance. Maybe a marble temple above it. And an access road made of gold bars. Or
this. Or whatever else looks suitable.