You kinda have to find what works for you, but a good rule of thumb is to double the time - e.g. review after 1 day, then 2 days, then 4, then 8, 16, etc. If you get a card wrong, it goes back to 1 day. Pretty soon, the cards you know will be permanently memorized, and should only get reviewed in 6 months or a year, etc.
