Incorporating by thirds means that you divide the dry ingredients into three parts and the liquid ingredients into half. Then you add them into the batter like this: 1. One third of the dry ingredients. Mix well. (see picture A above) 2. One half of the liquid ingredients. Mix well. (see picture B above) 3. One third of the dry ingredients. Mix well.(picture A) 4. One half of the liquid ingredients. Mix well. (picture B) 5. One third of the dry ingredients. Mix well. (picture A)