It is suggested to study Ling Fei Jing in regular script and the copybook of modern calligrapher Honggen Shen. Tian Yingzhang's and Pang Zhonghua's calligraphy is also good and worth seeing.
Calligraphy learning depends on perseverance. I suggest you dabble in the theoretical knowledge of calligraphy while practicing constantly. All kinds of calligraphy magazines and newspapers have good explanations, which are very helpful for your progress.
I wish you success in your studies!