Heat a large stock pot over medium heat. Add the olive oil, garlic and onion. Cook until the onion is translucent, about 8 minutes. Add the collard greens and cook, stirring constantly, until they are wilted, about 5 minutes. Add the rest of the ingredients.
Lower the heat to a simmer and cook covered for about 2 hours or until the collards are soft. Adjust seasonings as the cooking continues.
You can add more or use less vinegar than what is called for if you need to.