if you generate your own world, you can set how much points you can spend on embark. I dont spend all, but it allows me to take extra picks, since most of the idiots would otherwise just stand and stare at the other 2 working
metal can be found in any layer. If you have embarked in slightly hilly or mountainous terrain (not the biome, but with cliffs) you can see higher cliffs that dont have a dirt covering, often showing gems, metal ores or coal. I usually encounter metal before the 10th level, but since i dont really start my metal industry untill the 2nd winter (1st is when you arrive), its no big deal if i have to look around a bit.
If you have a few soil/clay top layers, use the one just above the rock to quickly move to a new place, then dig down a it, do some explorative mining etc
something nice happens when you hit a cavern. Or something bad. Spores start to infiltrate your corridors, enriching your underground clay, loam and sand with plants. It can be anoying because sometimes trees will grow where you dont want it, but the good thing is, you can now put your animals underground. Also, there are wood producing growths there. In the end, you can move entirely underground. why? Goblins...
at a note, at some point a forgotten beast will enter those caverns. If it can fly, it will fly up and destroy thet hatch and you'll see a lot of FUN. If its a stair made with (d), you can (b), (C), (u) over it to make a stair that only goes up, the way in will be blocked
Doors and hatches will NOT keep the strongest monsters out. Build bridges and raise them to make walls and just make walls. If possible, make it from magma safe stone since apparently they can still melt. Also, make traps, lots of traps. Experts have been advicing the large serrated disc, i tried it with copper, silver and iron and in all cases found it extremely effective, though it tends to splatter and throw bits and pieces around. If i could clean blood easily, i would like to know how.
As last, or first, resort, cages. Cage traps are the most ridiculously overpowered things in this world, being able to hold a full grown dragon that breathes fire with bits of wood or tin or lead or other stuff (tin and lead melt rather easily, wood burns... whats there to hold a firebreathing dragon? And how big is this cage?)
creatures with the tag "trapavoid" will still have to be dealt with tho