I almost exclusively build surface cities, so maybe I can help!
My first tip is to always immediately build a small structure around your first food stockpile with a door or bridge, so your dwarves can hide from danger. I can't tell you the number of times I've gotten 3 years into building a metropolis, then 10 goblins show up and kill everything because I've been building a grand cathedral instead of a saferoom.
Secondly, always turn your rock into blocks, because you get 4 blocks per stone, and they are lighter so they are transported faster. Keeping this in mind, its usually better to put your mason shops in the mines, then the block stockpiles on the surface, for faster building. If you're using wood, I don't think blocks offer an advantage other than its more difficult for enemies to climb.
It seemed to me, for example, that I had to individually craft each and every floor tile individually to start a new building on the surface.
I'm not entirely sure what you mean by this. You know you can make up to a 10x10 floor at once. Once you're constructing (b>C>f), you press u,m,p,h to resize the construction. Also, I always build walls first, and only floors where necessary, until the entire building is complete. Then you can go back and add the floors. It's faster this way because you often make last minute changes to the placing of walls, and then you have to go back and remove floors, which is tedious.
Lastly, you don't have to put
everything above ground (unless you really want to). For example, consider building a workdshop building, with the raw material stockpile in the basement, 1 z-level into the ground.
I hope this helps!