I've got a more convoluted way then most but convoluted is fun and gives you something to do. Start with just setting up a food/booze fort up near they surface. Nothing fancy at first, just build how you normally would. Once you're establish start digging down till you hit magma. I like to go out horizontally as well as vertically when I'm digging for magma simply because I like the idea of an underground highway connecting my two seperate forts.
Once you hit magma start digging out a new fort for metalworks. Bedrooms, dining halls, and anything else you keep in a normal fort. Once you got it all dug out seperate your two populations with Burrows (BURROWS ARE KEY!). Keep 4 or 5 dwarfs unassigned as runners, disable all labors but hauling on them. Exclude waste hauling if you tend to dump a lot of stone as it tends to keep them too busy to actually run material like they're suppose to. Add more dwarfs if you feel things aren't being moved quick enough.
What I do to keep food hauling simple is disable all raw foods (Plants, uncooked meats, etc) in all food stockpiles but your food producing fort. Instead only allow prepared food (Booze and cooked meals) in all your other forts. It makes dealing with food a lot easier since dwarfs won't haul plants and meats all the way to the other forts.
Repeat if you feel like it and you can have a whole fortress empire spanning the entire map. Usually I have each fort focus on one thing. It also finally eliminated the problems I had with too many jobless dwarfs and now my military have a reason to patrol the underground highways!