I have had good luck with just walking the dog, on lead, around the boundries of the property, keeping my body between the dog and the boundry. When the got expressed interest in straying outside the boundry, I would block them and keep on walking the boundry.
Without knowing how big of an area you're taking about, it's hard to say how long it will take.
We had about 2 1/2 acres and we were pretty consistent with it and we were confident within a couple of weeks.
Also, a strong, consistent recall is just as important.
He is your friend, your partner, your defender, your dog. You are his life, his love, his leader. He will be yours faithful and true~ to the last beat of his heart. You owe it to him to be worthy of such devotion. ~unknown