Pretty much what everyone else said. When mine got out, we looked everywhere for 2 days, then tried the bait idea (didn't work), then the flour trick (and found out it doesn't work if a dog sniffs through it).
Also, put a water bowl out on the floor near one of the walls. It won't necessarily help you find her, but at least she won't die of dehydration. When we finally found mine 6 days after he escaped, we put him back in his tank and he drank for a good minute straight.
EDIT: Nvm, see you found her. Yay! Congrats! 20 min, damn. You got lucky XD