On the question of props, the first question is, what IS a prop? Basically properties is everything that is not part of the set, the lighting, or costumes. What exactly that means changes from show to show. More specifically, properties usually break down into the areas:
Hand props are anything handled or carried by an actor. They include staffs, food, weapons, lanterns and candles, canes, staffs, parasols, and practically anything else an actor could or might pick up.
Personal props are props worn or carried by a particular actor and issued to him rather than stored on the prop table.
Set props include most obviously furniture. These are objects that add to the look of the setting, with which the actor interacts.
Set dressing consists of similar items, but which the actor doesn't usually handle. Some set dressings are "practicals", props like lamps or chandeliers that perform on stage as they do in real life. Trim props are a type of set dressing that hang on the walls, such as pictures, window dressing and curtains, and so on.
Also included in set dressing is anything on the floor. In the days when ground cloths were common, they were part of the properties department. Ground clothes are canvas drops painted to be floor. They were layed by starting down center, then were stretched out and back and secured with carpet tacks. Today props still includes rugs, carpets, and other floor coverings, but doesn't generally include a hard deck.
Greens are any plant, live or artificial.
Mechanical special effects are part of the prop department. That basically means any special effect that is not plugged in to operate. If a pull pin or a string operates a trick, it is a prop, but if an electric solenoid trips it, it is under electrics. Mechanical noise makers are props, but taped sound effects are electrics, and so on.
Atmospherics includes fogs, smokes, snow, etc.
Fogs are made using cryogenic (very cold) materials, which must be handled carefully to prevent injury.
Dry ice is frozen carbon dioxide. It produces a ground fog effect when dropped into hot water, or hot water is poured on it. Dry ice usually comes in blocks, and must be broken up before it is put into the dry-ice fogger.
To handle dry ice safely, you must use proper precautions. Never handle dry ice with bare skin; wear gloves. Use safety goggles when breaking up blocks to keep chips out of the eyes. To break a block up, first wrap it in a blanket to contain the chips, then break it into golf-ball size pieces with a hammer. Avoid contact with metal; the ice chunk will "scream" or "sing". Don't break the dry ice into powder, or it will "burst" into fog almost explosively!
Liquid nitrogen is also used to make fog by releasing slowly from its storage flask, where it condenses water vapor in the air. Keep clear of the valve and nozzle, as the escaping vapor is extremely cold and can freeze bare skin.
Smokes and hazes are usually made with glycol-based smoke machines. The nozzle gets very hot, and should not be touched. Be sure to use ONLY "fog" juice from the same manufacturer in a smoke machine. Each brand is different, and will not work properly or safely if mis-matched with a machine it was not designed for.
A snow effect can be done several ways. One is the snow cradle. The cradle is a long piece of muslin with slits cut in it at intervals of several inches and fastened as a trough between two battens on the fly system. Ground polyethylene or sometimes confetti is placed in the cradle, and when the batten is rocked up & down, the "snow" will sprinkle through the slits in the cradle.
Snow can also be made with commercial "snow" machines that spray out fine suds which fall like snow but which disappear with almost no residue.
Breakaways are props designed to break on cue. They may be made of brittle material, or be pre-broken and lightly glued back together with hot-melt glue, so as to break again easily.
Hot melt glue is a rubbery glue with a low melting point. It is useful for emergency repairs as it sets in less than a minute, but it is not very strong.
Other tasks traditionally assigned to props include: Setting the orchestra pit for a musical.
Setting stands & chairs for an orchestra concert.
Placing a piano for a recital. Once placed, the lid should be raised and the finish polished to remove smudges.
Placing the lectern for a speaker. A pitcher of water and a glass should be placed nearby for the speaker to use.
Laying and taping dance floor.
Sweeping the floor before and after load-in and moping the stage floor before each performance.
Getting the coffee & donuts before morning break!
Props must be organized for the show run. The key to this is to give every single prop a home where it belongs when not being used, that is easily checked to make sure nothing is missing.
The most common means of doing this is to use one or several props tables. A props table is simply a large table in the wings where props are laid out for use. Usually the table is covered with heavy paper which is divided into sections for each prop, appropriately labeled. The props are often outlined to make their proper place obvious. It is then quite simple to look over the table to see if anything is missing.
Seeing that props are in place on the props tables are the responsibility of both the props running crew and the actor who uses the prop. The crew should do preshow check AND each actor should check his own personal props before the show. Ideally props should always be in their place on the table when not in use. The actor will pick them up before an entrance and should replace props on the table when they exit.
Other options for show props:
Prop shelves and prop crates, are especially useful for travelling shows. These are usually not as easy to set up, and may be harder to check than tables, but they make setup and tear down very efficient.
The key to any system is that there BE a system and that it be easy to check and maintain so that props are always available when needed.