First of all, there is an interesting thing with the tickets. You don't need to buy a ticket to a certain station, you can simply buy one ticket and enter the Metro at any station. Once you have crossed the ticket gate on the way into the Metro and haven't yet crossed it on the way outside, you can go anywhere you want on any train you like and in any direction you need. It is also important to note that there's no time limit. Tickets are only limited by the amount of times you cross the ticket gate. Thus, there are tickets for 1, 2, 5, 10, 20, 60 times and tickets for unlimited amount of 'trips' (so-called 'smart cards'). That means, your ticket becomes invalid when you've already crossed the ticket gate for 1, 2, 5, 10, 20, 60 times respectively. 'Smart cards' are valid for a month, while tickets for 1 and 2 times are valid for 5 days from the moment of purchase, tickets for 5, 10, 20, 60 times are valid for 45 days from the moment of purchase. So, if you don't use them within this period of time, your ticket also becomes invalid, even if you have never used it.

Normally, all the lines but "Kol'tsevaya"which is a belt line, are a straight way from one side of Moscow to the opposite one. You can enter on any station and exit on any of them as well. But two lines are partly interchangeable. Gray and green lines have a joint depot on "Varshavskaya" station. So, don't be surprised if after a good sleep in the carriage on the way from "Rechnoy vokzal" to "Krasnogvardeyskaya" you find yourself on a different line on "Varshavskaya" station. Trains go both there and to "Krasnogvardeyskaya" of the green line. Train to "Varshavskaya" goes from "Rechnoy vokzal" at intervals and keeps the green line until "Kashirskaya". In order not to be caught in a trap of this 9 3/4 platform you should listen to the announcements in the carriage on green line very carefully. The trains of the Kakhovskaya line are safe because they go straight from "Kashirskaya" to "Kakhovskaya" without any surprises.

The "Kashirskaya" station is also interesting because it is one of three cross-switch stations. They are "Kashirskaya", "Kitay-Gorod" and "Tretyakovskaya". On these stations trains of different lines share the platform. It is very comfortable for switching the lines because you have only to go upstairs to take the train of another line. At the same time it is very uncomfortable for arranging meetings there, because you can stand just opposite one another and still you won't see each other. 

If you forgot or lost something in the Metro don't be upset beforehand. There is a chance that the umbrella you have left on the bench or you documents are in the lost property office. You can go to the station "Universitet" and take your things back. The lost property office is in the southern entrance hall of the station. You'll definitely find the hall if you go upstairs in the middle of the platform. 

To be the first to enter the carriage sometimes may be important for some reasons. If you want to find out where the door of the carriage is before the train appears on the platform, look down. The Metro is quite old and millions of passengers' feet wore the stone of the floor out near the places where the doors of carriage are when it comes.

Also, without knowing any Russian you can understand whether you are approaching the center of the city or going to it´s outskirts by the voice of announcements in the carriage. On the way to the center a man says, what´s the next station, and woman´s voice shows that you are returning from the center of the city. These voices change one another in the middle of each radial line. On the belt line you hear mans voice when going clockwise and woman's voice when going counterclockwise.