Start with camera phone, or camera, legal pad, tape measure and pen. Go room by room, take notes by room, and photo the page for that room last. Take photos of all things in each room, it doesn’t have to be of each item.
It is not necessary to have a photo associated with each asset, and is not even necessary to have any photos if your divisees don’t need them to know what is described by the item name. Often the photos are more so the lister can be sure they list all assets in a room and can refer to those photos room by room.
Photos can be helpful to have a photo associated when differentiating jewelry, collectibles, many oil paintings, etc. or when heirs may not have seen the items for a long time. (See tips of photographing items video) Otherwise, taking the time to associate a photo with each item is usually a waste of time when people already have a good understanding by the item name and which room it is in.