Positioning and Contact Copy
As mentioned with haltering, horses generally are handled from the left. Walk with the horse’s head, neck or shoulder alongside you. If you walk ahead of the horse, he might startle and run over you, push you or even bite. If you walk too far behind the neck, he may learn to pull you, you may be outside his line of vision and startle him and he will see things before you do, potentially catching you unaware.
The main thing is to be positioned where you can: A) use your body and sight to guide the horse, B) move to safety if they move suddenly forward or sideways and C) be within their field of vision for comfort and safety.
The contact with the lead rope should be short enough to maintain control of the head, yet loose enough so that the horse does not feel restricted. In other words, the horse should feel no pressure from your hand as long as he/she is moving forward or standing obediently.
If the horse does pull back, especially if at all fearful, it is important to go with them for a few steps rather than trying to hold them too tightly too quickly. Resisting will likely just make them more fearful and they will pull harder. It can be a fine line to find just the right timing and amount of pressure to hold a frightened or difficult horse. Just be aware that your chances of winning a pulling match are very slim.
From your instructor: The lead rope must never be looped around your hand or any other body part. Even looping it with big loops that could tighten when the horse pulls is a major risk. Fold the rope back and forth across your palm instead. Both hands should always be on the rope, the right hand holding the lead a few hands lengths under the nose and the left hand holding the slack.