1. Heat milk to 180 °F.
2. Cool milk to 115 °F and add yogurt culture. (Culture usage: 1/8 tsp per quart of milk or 1/4 tsp for 1-4 gallons of milk.)
3. Stir in gently until dissolved.
4. Hold temperature at 105 to 110 °F for approximately 8 hours.
5. Refrigerate
6. For added body you can place yogurt in a colander draped with cheesecloth or butter muslin.  The result will be a thicker, more creamy yogurt.
7. For enhanced flavor, add a few drops of vanilla when adding the culture.

Making yogurt is really very simple.  There are no hard and fast rules except to heat the milk, add the culture and let it incubate.  I have heated my milk to 180 F but I have also just let it come to room temperature before adding the culture.  I have added the culture at 75F and at 110F and the yogurt still seems to set just fine.  I have found that the higher the temperature, the smoother your yogurt will be in the end.  Some recipes call for you to hold the temperature at 180 for 30 minutes for a smoother, thicker yogurt.