Combine 1/2 cup flour and 1/3 cup of water in a one quart jar and mix thoroughly. Cover with a breathable fabric such as a cotton tea towel and secure with a rubber band. Set in a draft free place.
The next day, stir the starter and add another 1/2 cup flour and 1/3 cups water. Stir to mix. Re-cover and set aside again.
On the third day, the starter should look bubbly and may have separated into layers. Stir everything back together, then pour 1/2 cup of the starter into a new, clean jar. To this new jar, add 1/4 cup of water and 1/2 cup of flour and stir well. Cover with the same breathable fabric and set aside.
On day 4, increase the feedings to twice a day. Feed 1/4 cup of water and 1/2 cup of flour morning and night, stirring well each time. Once a day, you will need to discard 1/2 cup of starter, maybe a bit more, depending on the size of your container.
Repeat step 4 on day 5, day 6, and day 7.
At the end of day 7, check to see if the starter is ready for baking. It should be visibly bubbly and have a sour smell. A few tablespoons should float in a glass of water, and/ or you should be the volume of the starter double 8 hours after a feeding.