some suggest turning off all the lights, radio and accessories. In addition, though, pull off one lead from the 6V battery terminal and connect the jumper to the free lead. This eliminates the danger of battery explosion when current surges into the 6V battery.
Once the jumper is connected, turn on the ignition and quickly crank the car until it starts. Do not delay or the 12 V could damage the instruments. As soon as the engine starts, disconnect the jumper and jam the lead back onto the 6V battery terminal. If you're lucky, the engine will keep running through this transition (keep the revs up so it will run on the generator during brief time the battery lead is not connected) and you'll be on your way.
or you could just push it a few feet and pop the clutch