Advanced players, how do you visualize positions, and how did you get better?

So I understand the super GMs can visualize positions exactly in their heads and can play blindfold games without much trouble.

I can't do this at all, and my visualization is terrible which makes it hard for me to calculate beyond ~4 moves deep.  I understand that when the good players calculate lines, they are able to reach certain positions in their heads, and then calculate from that position, whereas every single line I calculate has to come from the original position.

My visualization is mediocre in the endgame, but it's the opening and middle game that I struggle to calculate with precision.

How is it exactly that you visualize, and how can I get better at it?

I'm a big fan of practice what you want to get better at.

You want to visualize better? Then do a lot of visualization during your games and study time. Yes, you're going to be terrible at first, just like everyone else.

I accidentally chose to solve tactic puzzles in a bad way for tactics, but a good way for visualization. I tried to see the whole solution, including all relevant variations, to the very end before moving the first piece. What I mean is I tried to actually visualize clearly the final position (I'd move my eyes around the board saying where each piece and pawn was for the end position for example). If I was having trouble seeing it, this basically involved calculating to the end over and over until I had the final position basically memorized.

I also went through an endgame book and got tired of setting up positions over and over, so I tried to work though the main line and any variations in my head. Sometimes they were complicated so I would give in and set it up on my board, but I always tried to go as far as I could in my head first.

I did these things accidentally, without intending to improve my visualization, but they helped.

y0u d0 not need t0 visualize anything ,  just  y0u believe in good m0ves. 

Some books recommend training your visualisation skills to improve your chess.  The slightly dubious logic behind this is that strong players are good at blindfold play so by improving your blindfold ability you'll get stronger.

I think they have it back to front.  I think it is that by playing a  lot of chess and becoming stronger that you become better able to visualise positions, both in blindfold play, and when calculating variations and assessing future positions in a game with a board and pieces (which may be physical or electronic).

Of course this is an unscientific belief, based entirely on my own experience.  On the same basis I question whether being able to play blindfold with ease necessarily makes you a strong player.  I can play blindfold chess with ease.  I can envisage positions just as well with or without a board.  The problem is that whether I have a board or not I do not find such good moves as really strong players.

I still conclude that what matters most is not whether or not you can accurately visualise and assess future positions, but whetehr your subconscious mind has enough chess knowledge and understanding to bring the important possibilities to your conscious attention.

I reckon that  trying to improve your visualisation skills directly, with special exercises is not very helpful. The time and effort would be better spent studying chess.