What should I do if Mandarin is not good?

Mandarin is not good, you can try the following methods:

Do ten minutes of oral practice every day. In fact, sometimes we can't speak Mandarin well because our tongues are not flexible. You can practice oral English at this time.

Oral practice can exercise the flexibility of our mouth and tongue. Essentials of oral practice: close your mouth, then move your tongue up and down, left and right in your mouth, first clockwise 10 times, then counterclockwise 10 times. Practice until your tongue feels a little tired.

Practice your lips. Shut your mouth, then exhale hard until your mouth is full of gas, and then spit it out with the strength of your lips. This action can effectively practice your lips.

Change the tone. If you want to change your accent, you must first change your accent. We can usually watch how other announcers pronounce and learn their accents.

Introduction to Putonghua:

Putonghua is another name of modern standard Chinese, which is a common language with Beijing accent as the standard pronunciation, northern Mandarin as the basic dialect and typical modern vernacular as the grammatical norm. Chinese is different from Putonghua. The promotion of Putonghua is not to eliminate dialects artificially, but mainly to eliminate dialect barriers, which is conducive to social communication and is not contradictory to people's use of inherited dialects.

Refer to the above? Baidu Encyclopedia-Mandarin