Go to an office supply store and buy some tags that you can write on.

Then go around your house, particularly the basement, and tag all those things that could cause trouble.   Put a tag on all the water shut-off valves, particularly the main shut-off valve and valves leading to outside hose bibs.  Put a tag on all the gas shut-off valves.  Put a tag on anything that you’d like to be able to identify quickly in an emergency.  Tag the hot water heater, the furnace, the electric panel, etc.

Once everything is identified, take your family on a tour of the house and point out where everything is.  It could save you a lot of trouble and money if you have a leak or other emergency and you need to quickly shut something off (particularly if you get a phone call from someone at your house who isn’t house-savvy, say a teen-age son or daughter screaming at you about a leaking water pipe!).