hi I have planned to visit beijing tianjin and guangzhou. would u direct me how I vist with 8 days

If you have told me the entering and leaving cities, I will give you more practical plans. Anyway, here is my general suggestion:
Three days in BJ, two days in Tianjin and three days in Guangzhou.

Best transportation between BJ and Tianjin should be intercity bullet trains and to Guangzhou from either of the two cities, plane will be most time-saving.