"Inner board"

Hi again,
playing blindfold is indeed one of the best methods to improve your inner vision of the board. Apart from the useful things mentioned in the post and link above you can start with easier tasks, like telling the colour of a certain square without looking at the board or listing all white diagonals with more than two squares by name or how many moves a knight on a given square would need to reach a certain other one. Obviously there are lots of similar exercises you can even invent yourself.
Apart from that, if you are working with a chessbook (no matter how many diagrams there are) related to any chess topic, try to play through at least the given side variations without executing the moves on the board. Only after you think you got the point of the variation, actually move the pieces on your board.
Most top players, I've read, don't even look on the chess board when calculating. Instead they gaze into nowhere and make their calculations on their "inner board". Personally I do not possess the ability to do so and am wondering how one could train to manage such a thing. Or should I not even bother, since I'm yet merely at ~1300 in OTB play? I feel my tactics are quite lacking, which is why I ask. Solving chess puzzles is fine but it seems like I'm just practicing pattern recognition, which I'm sure is useful, but it really doesn't help improve my ability to calculate many moves ahead!