keep checking her camera to know which phass she's in
Foxy has 4 phases
1. Hiding
2. Peeking
3. Preparing
4. Attacking
phases 1 to 3 only serve to you as a indicator of how close she is to attacking you, when you see she's at phase 3 check her camera more frequently and get ready for her attack
when she disappears from her camera quickly change to te left corridor camera to catch a glaze at her and then close the left door until she stops banging your door
if you don't catch her running in the corridor she'll drain A LOT of your power when banging the door for some reason.