Dishing is the same as for any wheel, as is spoke tension - if you can build a conventional rear then discs hold no extra challenge. What is more important is the direction of spoke lacing - look at your rear wheel and notice how the outer (stronger) spokes 'pull' the rim when you pedal. Now the force from a disk brake acts in the opposite direction so on your rear you will have the outer spoke lacing in the opposite direction on the disc side. For the front make sure that again at least on the brake side the outer spokes go forwards so they are tensioned as you brake. Disc brakes mean radial front lacing gets a big no.