Store your starter in the refrigerator: The night before baking bread, take the starter out of the fridge. There may be a bit of light amber or clear liquid on top. Either drain this off, or stir it in, your choice; it's simply a byproduct from the fermenting yeast.
Add the 3/4 cup flour and 1/2 cup lukewarm water to the remaining starter. Mix until smooth, and cover.
Allow the starter to rest at room temperature (about 70°F) overnight and then you can use it. CAUTION: Use a large container so the starter has lots of room to expand or you can end up with a mess to clean up.