Both feet point in the same direction, the gaze and shoulders are directed towards the end point of the slackline, the arms are at a 90 degree angle to the slackline (slalckline and arms form a '+' sign), feet at least hip-width apart, knees slightly bent.
Lighten the load:
Perform the exercise close to the attachment; stretch the slackline tightly over a short distance (3-5m); sit a partner in the middle of the slackline to dampen the initial trembling; help a partner by holding their hand (always go with the balancing movement and only stabilise if the slackliner is about to fall).
Make it harder:
Stretch the slackline over a long distance.