Iv'e been asked a couple times recently how I feed my starter, so I'll post the answer here:
Nowadays, I usually feed it about 6 hours before I use it. I keep about a pint. To feed, I add about a pint of water (50:50 starter:water) then discard half and add enough flour to make it a thick batter consistency. It would just barely pour.
It's less important precisely how you feed your culture than it is that you do it the same way every time. This will help you achieve consistent, predictable results.