What defensive tactics can a company use to gain competitive advantage?

What defensive tactics can a company use to gain competitive advantage?
Raise structural barriers through: offering full line of products signing exclusive distribution agreements raising buyer switching costs by offering lower cost for training raising cost for competition to gain trial users by decreasing your cost increasing the scale of economies patents and licensing limiting access to facilities sigining exclusive contracts with suppliers and buying key locations avoiding suppliers who deal with competition encouraging the government to increase barriers.Increase expected retalitation by making a big deal of a small thing.Lower the inducement for attack by keeping pricing low and constantly decreasing costs to keep profit high.