Things that you will need is:
A good digital camera that puts the date and time on the photos ( this proves that you were at the property when you say that you were). All the companies want the date and time on the photos.
A big memory card or two.
Extra batteries for the camera.
A computer to be able to upload the photos to the company that you are taking the photos for.
The photos that you need to take every time that you go to the house are:
The address on the house or curb.
All sides of the house- front, both sides, back of the house, from the corners of the property showing the yard, photos of the street that it is on.
Before, during and after photos of all work that you are doing.
Photos of every room in the house.
If the appliances are in the home or not.
Any damage that might have been done to the home, like holes in the wall, water damage, standing water.
Things that could be a hazard to people walking into the property- trip hazards, health hazards (mold, rotting food), electric wires that are exposed and could be live.
There could be things that are missing, like- light fixtures, light switch covers, cabinets, sinks,toilets, showers and more.
If you will be bidding on things make sure to get photos of the things that you will be bidding on, things like the damage that could be fixed.The health hazards that will need to be addressed, doing a trashout.
This video gives a good idea of what I am saying here.
D&D Taking Out The Trash, LLC