You can buy copybooks in bookstores or websites. The experience of learning books and practicing calligraphy in ancient and modern times proves that copying copybooks is the only way and an effective method. Copying is to put the copybook under transparent calligraphy paper and draw it with strokes according to the words appearing on the copybook. The handwriting required to be described cannot exceed the stroke trajectory of the words on the copybook.
If copying a brush copybook, the strokes described should follow the center line of the strokes on the copybook; If you copy a pen copybook, the strokes described should be exactly the same as those of the words on the copybook. In this way, over time, you can learn the line trace and font structure of the words on the copybook.