maxed out plant gatherer, maxed out brewer, maxed out cook, miner (probably but not necessarily maxed out), mason (ditto), and an maxed out armorsmith/weaponsmith. give the smith a backup skill, like mechanic or building designer. the seventh is up to taste; any combination of novice woodcutter, novice carpender, ambusher (which will give a free crossbow and set of leather armor), maxed out glassdwarf or maxed out jeweler is reasonable. If you don't give the seventh dwarf carpendry, give it to the brewer (brewers who make their own barrels never stop working). Take a few seeds (you can always get more by gathering inside the mountain), some meat (at least one of every cheap kind), some alcohol (about twenty to thirty units, with n5+1 of each type), two dogs, one pick and one axe.
this build is only newbie-worthy on maps that are good or neutral with heavy vegetation, so make sure you pick one--avoid anything that sounds bad, like sinister or terrifying.
when you get there, disable all but one or two hauling tasks for each dwarf, and give none to the miner and the gatherer. [d]esignate some plants to be gathered and a food stockpile to put them in. build a still and a kitchen. I had enough to feed my dwarves just by cooking the seeds of the outdoor plants I gathered, but many people like to cook the alcohol (all this is done through the workshops and the z menu). Following this you will have plunty of food and booze and enough time to build your fort as deep as you like.
Also, what is causing your forts to fail? External violence, internal strife, or simple starvation? I assumed you were having problems with your food supply, but if it is something else you might want to try something completely different than the above.