How effectively train Systema for real self defense?

        To answer this question, it is necessary to remove all illusions from the eyes of  practitioners. And  not only  Systema community, but also for all those who practice any other martial arts.
It's not difficult to do if your mind has remained not blinded  by TV,  Internet and of course ... a sport.
        If you have practiced sport martial arts for many years, it is not easy for you to remove your illusions. And this is expressed in the goals pursued by every practicing martial artist.

       If you are an athlete and participate in boxing competitions, wrestling, taekwondo, karate or any other  sport fights,  it is your main goal is to win these competions.

         It is quite a worthy goal for a 15 year old teenager who needs self-assertion and self-knowledge in this world. But if you are already 30, 40, 50 years old or more, and you continue to train in sports techniques, then you are in deep illusion (delusion) about your skill and goals.
And accordingly, you are in illusions about the methods of your preparation.

Yes, you can probably win this sport sparring in the following conditions:

1. On the tatami or in the boxing ring, on a soft surface;
2. In special clothes and shoes determined by the competition rules;
3. With the supervision of judges and doctors who is ready at any time to stop sparring;
4. According to strict rules; for example, your opponent can not beat you in the groin, spine and joints; he can not affect  (act) to your eyes, ears, hair; he can not bite you, cut you; to throw sand or alcohol in your eyes and much more.
5. Your sparring will  be only against one opponent;
6. Against only one opponent with the same weight and gender;
As you understand, this fight is conditional and cardinally different from a real street fight and a real extreme situation.

And here you can see that conditions of a real combat situation (real battle) that can occur:

1. At night, with a strong wind and in the pouring rain;
2. Knee deep in snow, on ice, in the water (river, sea) or in the mountains, on a steep staircase, in a very cramped room cluttered with furniture or in elevator;
3. In a car, bus, plane or any other kind of transport;
4. At this point you can be dressed in a winter coat, jacket and heavy shoes or vice versa you can  be in only swimming trunks and barefoot;
5. You can be attacked by several people and naturally they can be with a weapon (knife, piece of metal pipe or  gun).  As you understand it will not be a rubber or wooden training knifes which you used useally in your trainings;
6. Your opponent may be mentally ill when he is  the most aggressive person;
 in a state of alcoholic or narcotic intoxication. It is these states that are characterized by unpredictability and it's the maximum  dangerous for the defending one.
7. You can be attacked by unexpectedly from behind with a hit a heavy object to your head or  putted your neck in the noose;
8. You can be attacked  at high speed by car, by motorcycle and any others.
9. You can be  seriously wounded,  but no one will stop the fight and will not give you first aid.
10. At the moment of the attack to you, you can be sick, tired, in a state of intoxication or  in a state of affect;
As you can see, all of the above is simply unacceptable to a   sports  martial arts. Therefore, the training methods should be fundamentally different.

 And now, you try to analyze your workouts at your sports club or in your Systema group.

1. Where do you train? In the gym or does it happen on the stairs, on the asphalt, on the snow or in the water?
2. In what clothes and shoes did you train usually? How  close is it to your everyday clothes and shoes?
3. With which objects (weapons) did you train usually?
4. Who is your partner and how ready is he to at least slightly approach to the role of a real attacker? How did he capture you? How did he  strikes you? What does he scream  or what kind of role he plays?
5. And so on. Try to go  through all these points of the conditions of real combat, which are indicated above and you should compare it with your conditions.
You will see very clearly what illusion you are in. How far is your training conditions from real life conditions (real battle for survival).
In this answer I have touched on only a few aspects that relate to the training system for real life.
Only short remark about who is your teacher of Systema or any other martial art?
How much your teacher (instructor, guru, trainer)  has experience of real participation in hostilities, real work in the police, where it is necessary to detain dangerous criminals every day, or at least an ordinary security guard in a nightclubs in a criminal area.
If your teacher, coach, instructor is only an athlete, or in general, he is an office worker, then naturally he will be able to teach you only sports skills or some illusions.
The dog will not be able to teach his puppies to climb trees, but a cat will teach it to do wonderfully.