Here, I will only share my personal experience for increasing external links:
1. Through webmaster tool websites, query the website and increase backlinks.
Nowadays, many webmaster tools provide services to check Alexa rankings, Google PR values, and search engine indexing statuses. After using these tools, they record the query information in their databases and leave a link to the queried website. There are many such batch query tools, for example: Lu SongSong's automated website promotion machine.
To be honest, I rarely use this tool, but I installed an extension tool in Chrome that can query website information, which might have some effect.
2. Submit webpages to Digg-like websites.
There are very few Digg-like websites left now, even Digg itself is struggling. Below, I will share some Chinese Digg-like websites that are still active.
Mopu Tuike: http://tk.mop.com/
Xian Guo Hotspots: http://xianguo.com/hot (requires RSS submission)
Qike Discovery: http://www.diglog.com/
Waakee Information: http://www.waakee.com/
5D Information: http://news.5d.cn/
3. Post and reply on forums with URLs.
WordPress Chinese Forum
Tianya Community: By using the Chrome extension "Tianya Assistant," you can modify your personal signature to include a URL. Be clever about it to avoid getting banned.
4. Write soft articles.
Baidu Wenku, Baidu Experience, various blogs, etc.
And more...