It depends on the tiller type. Most tillers are designed to be pushed forward with the operator in the back, but a few models work best when pulled backward. Since electric tillers have forward-rotating tines, pulling the tiller backward creates greater friction and torque. This allows the tines to dig more deeply into the ground and helps prevent your tiller from bouncing along the ground. Be sure to read the manufacturer's instructions carefully so you have a good understanding of how your tiller works before heading out to the garden.