im 14 so still young, but I dabble in blindfold chess. the best way that i know of is too play 10 moves in a game looking away from the board, then play the 10 moves on the board and do that for the whole game. Then you will keep increasing how many moves you play looking away until you can play a game blindfolded. Another way is to just start visualizing but i found that method much harder.
Visualizing the board in your head

I am 28 and I still made some progress in visualization. Making progress as an adult might require the ability to enjoy one's growing capabilities while they are still at a low level and a playful approach. What do I mean by that?
You can start with that chess.com vision training, find the squares on the board fast, get used to the square names from both the black and the white perspective. And if you are good at it, ask yourself without seeing the board where the squares are, what colour they have, etc. Imagine a piece on the board and try to move it around just in your imagination. Try to solve tactics and visualize the end position. Sometimes it is enough to just focus on a specific area of the board. Try to play your openings in your mind or even play some nonsensical moves and just visualize the pieces and where they can go to and so on and so forth. You do not need anything for that, it is just a kind of daydreaming.
And maybe you have a kind and patient person around you, who likes to play a game with you being blindfolded. At a very low level and quite slowly, I am now able to play and win a game this way.
To give you an impression, I can visualize a quadrant of the board without problems and put important pieces from other quadrants also into the equation. If I try to visualize the whole board it gets blurred, meaning that I still know the placement of the pieces but not their relations to each other, i.e. I do not see immediately where they can go to and how they can work together.
It is definitely worth the effort and a nice way to bridge waiting time. So go for it!

Try memorizing a game PGN move by move and visulaising it. If it helps look at the moves being played then replay them in your mind, then start from turn one to the last one you memorized. Repeat until you complete the game. This should familiarise your mind with the positions. It is a good idea to get a few different games in different openings and visualise them from both sides of the board. This should give your brain some reference points to work with and practice for when you play live games. This is just a training method to get you started just dont memorize any old rubbish try and find some master games.
Hey everyone,
I've been thinking a lot about visualization recently. I've noticed that good players tend to do a lot of calculating while looking away, while I stare at the board and visualize the pieces moving around. I'm really interested in gaining the ability to see an exact chessboard in my head but i'm not sure the most effective way to practice doing so. I'm slightly worried that it's easier to learn as a child when most good players began studying the game, as i'm turning 24 soon and the old neurons are slowing down. What do you guys think, have any of you learned how to do this at an older age?
Cheers