Hey all. I'm going to China this October for 3 weeks, for the first time in over a decade. I speak Chinese, but I'm afraid I've been away for so long that I'm going to be confused by how much everything has changed. Would greatly appreciate any tips on: where to book hotels, where and when to buy tickets for the 高铁, how to pay for the subway (in Shenzhen, Guangzhou, Hangzhou, and Beijing), how to find restaurants in advance (to plan out my days, kinda like Yelp in the west), and anything else I might need to know? Websites/resources in Chinese are fine.
I already have Alipay and Wechat with my credit card linked for payment, which I assume should be good for most payments there?
Besides those things, if you're a local of/familiar with Shenzhen, Guangzhou, or Hangzhou, I'd also appreciate tips on must-see sights. I've been to BJ/GZ/SZ before but I'm mostly only familiar with Beijing.