Fun or fun?
Fun--Don't build any traps. Rely on war animals as your first line of defense. Only import metal gear, everything home-made needs to be wood, bone, or shell. Kill human caravans and offer elven ones wood before killing all but one of them. Refuse to wall yourself in. Expose yourself to all three cavern layers. Etc.
Not Fun, but fun--Generate a high-minerals world, locate a place with clay and plenty of minerals, embark with two militia dwarves that have skills in teaching, axe/speardwarfship, and a point in civilian skills; optionallly add a hunter/marksdwarf. Get plenty of clay and begin building fortifications and walls and stuff with it. Locate ores and magma ASAP. If you have both iron and flux, prepare your steelmaking industries but don't actually start churning out gear yet. Meanwhile, recruit any migrants without useful skills into either the militia (under your two Starting Seven dwarves) or the Builders' League (which, ideally, will also be a backup wrestling/misc-weapons squad). Any dwarves with military skills in the militia will be put into a squad using their weapon of choice and lead by the dwarf with the highest teaching and military skills, in that order; all others will be put into squads, starting with those under three dwarves and then adding to spear-, axe-, marks-, and optionally hammer-dwarves. Once your gear and wildlife coincide so that the dwarves can kill the wildlife without too much danger, send them out to kill the wildlife for food and preactice. Optionally, use a danger room to speed things up. By winter, choose a few dwarves with proper personality traits (like liking to help others and being impulsive) to be your medical staff--they are exempt from almost all non-medical work, perhaps letting them haul non-dangerous stuff during times of peace. Also (optionally) locate some similarly-endowed dwarves in the militia, and put them into a special "rescue" squad. They get decent armor and a shield, as well as perhaps a weapon, and have most labors disabled. Once there are some wounded, they should rush out to save the wounded; make sure they also have feeding wounded and perhaps some basic medical skills enabled. You'll probably start getting thieves and perhaps ambushes, so start churning out gear before the second spring. Improvise from there; no plan survives contact with the enemy, and the enemy's well on its way.