How in the world do I:
A: Train my military to not be pushovers.
and
B: Equip them so that they can kill things.
An "ambush" of 4 goblins tend to kill 4 or 5 or 6 of my dwarven squad members, for some reason, despite them being assigned "individual choice" of weapons, and to train whenever they're not doing anything else ("individual combat drill" is the only thing that I see listed for their activity).
Best Answer
Training: danger rooms (a room full of lever-operated upright wooden training spears). This is considered an exploit by some, because of its absurd effectiveness, but if you want your dwarves to be real good at fighting real fast, this is the way to do it. Remember to use wooden training spears, which are virtually harmless, and not menacing spikes, which are deadly weapons even when made of wood. Stick 10 spears in each trap for maximum effectiveness, and remember to give your dwarves armor, shields and weapons of a type you want them to train with. Removing shields will accelerate the speed of weapon skill training, but will obviously stop shield user training.
Equipment: iron armor at the bare minimum, steel if possible. A dwarf can (and should) wear chain mail, a breastplate, greaves, boots, gloves, a helmet, and a cloak. For weapons, axes and hammers are generally the best, axes excelling against unarmored enemies and hammers against armored enemies. Chance to hit is increased for masterwork (x2) and artifact (x3) weapons (less skilled soldiers will get greater benefits from high-quality weapons than legendary soldiers), so train up your weaponsmith. All dwarves should also carry a shield, you can get away with shields made of wood or inferior metals if you are light on steel.
Scouting: Remember that not all goblins are created equal. There is little you can do to prepare your dwarves to fight Goblin Lashers. People call them Sith Warriors for a reason: whips (and scourges) are effectively lightsabers, penetrating most armor due to a very small contact area and a massive velocity, however high Shield User and Dodger skills will give a good boost to your dwarves' chances. Have a backup plan to deal with an entire squad of Lashers. Goblin Bowmen are also dangerous, try fighting them in winding corridors to prevent them from shooting up your advancing dwarves, or counter them with your own elevated crossbow-wielding dwarves behind fortifications. All other goblin weapon specialties are pretty much equivalent; well-armored and armed dwarves should be able to deal with them relatively safely.