This is how I currently make sourdough bread, constantly evolving and now including new steps from Maiana's recipe.
750g flour (Maiana uses 100% white spelt, and it's awesome; I use ~200g whole spelt, and 550g either white spelt or white bread flour (the former has slightly better flavor, the latter has slightly better rise, and both are great). You can also use all white bread flour, which might need a tiny bit more water to make a dough that isn't too stiff)
450g water (can substitute up the entire amount of water with leftover cooked oat porridge, the soupier the better. You may need to add 25g or more water if you use a lot of oats; the texture is moist with an open and delicious crumb)
150g active/fed sourdough starter
1 T. salt
Mix together the flour, water (or water/oats), and starter. You should have a dough that holds its shape, but isn't too dry, and not too loose. It should be soft, and a bit sticky. Let this dough sit on the counter for half an hour or so, for an "autolyze" (no-salt fermentation to improve the texture).
After half an hour, sprinkle the salt on top and incorporate it into the dough. Cover the bowl tightly and let it sit on the counter for about 6 hours, until approximately doubled in size. (If the dough seems not quite mixed evenly at the beginning, you can do a couple of "stretch and folds" every half an hour, about three times, but make sure there are no pockets of flour to start.)
After six hours, line a clean large bowl (with lid) with parchment paper. Scrape the dough out of its rising vessel and fold it under itself a few times to deflate the dough and stretch its "skin" around itself. I find doing it quickly with wet hands works the best. Place the ball of dough, seam side down, into the parchment paper-lined bowl, cover tightly, and refrigerate. 36-48 hours in the fridge seems optimal, but as little as 12 hours will work, and up to about 72 hours. (If the dough sinks and seems less animated the night before you're planning to bake, you can take it out of the parchment, repeat the folding-under-itself process again, and put it back in the parchment in the fridge until the next day. This will strengthen the dough and make for a better rise.)
When you're ready to bake, preheat a cast iron dutch oven with lid for half an hour in a ~450f oven. When it's preheated, carefully transfer the bread (just out of the fridge) using its parchment paper sling into the preheated dutch oven. Quickly make a few shallow slashes in the loaf's top crust, cover with the preheated lid, and bake for approximately 45 minutes, until the bread is 205-210f using an instant read thermometer. Remove from the pan to cool before slicing.