This article is from the Sourdough Starters FAQ, by Brian Dixon briandixon at hotmail.com.
1. Using 1 cup of starter, 1 cup of 85 degrees tap water (don't worry
about minerals or fluoride), and approximately 1 1/2 cups all-purpose
white flour, proof your starter for 12 hours at 85 degrees.
Maintenance of temperature is very important.
2. Examine the starter to determine what stage it is. Assuming you
didn't overheat it, it should be "flat", "barely living", or
"healthy." If your starter is "healthy," you're done. Remember the
clues to identifying non-healthy starter: low number of bubbles,
early hooch, gelatinous consistency, no froth on top, or any two or
more of these symptoms.
3. If your starter isn't healthy yet, stir it well and refrigerate it
for no less than 12 hours.
4. Remove the starter from the refrigerator and go to step 1). This
iterative process needs to be repeated a few times ( usually around 4
or 5 times or so unless you were lucky. A lot of the home-dried
starters revive MUCH quicker than this.
 
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