Do not go into standing water.
Ensure power is shut off.
Check your sump pump to ensure it's running / working properly.
Clear out your downspouts and ensure they are extended away from the house.
Take pictures and video to document observations.
Clear out window wells.
Protect yourself from another rainstorm.
Move valuable items, cut away water damaged drywall or wood, pull back carpet, use fans.
Add a dehumidification system.