Play more standard chess.
It seems strange, I know, but it just happens that your blindfold skills increase with your standard skills.
The reason is that you are more likely to spot patterns that are easier to remember than just the position of pieces.
There were an interesting scientific study (I don't have the reference) where people had to memorize positions on a chess board. When the pieces were randomly set up, strong chess players did no better than the group that hadn't played chess in his life, but when it came to real positions the chess players memorized it much better, rarely misplaced single pieces but instead translated groups of pieces.
am reading improve your chess now and an interesting chapter on blindfold chess. One way is to use diagrams in your head to move and track the position. Are there any other suggestions on how to improve visualization and calculation skills?