Cinaforum and East Asia Forum are an excellent information websites on China; topics vary with a prevalence of geopolitics and economics.
An information blog on India is Indika.
Aseanup is a website providing useful economic information on ASEAN countries. It is dedicated to potential investors in the area and thus contains guides on markets, taxation, incentives, etc. in individual countries.
Also very useful is Eastonline with information on the entire Asia Pacific area.
For detailed geopolitical information on each country, an excellent source is the C.I.A. World Factbook.   

Airlines & Hotels.
Our preference goes to Emirates for the large number of destinations and the excellent value for money (if the destination is Australia/New Zealand, the choice is almost obligatory considering the ties with Qantas).
All hotel reservations are made online, and besides the well-known Booking, also recommended is C-Trip, essential for booking hotels and domestic flights in China.
To manage the travel calendar (flights, reservations, and appointments), the excellent Worldmate app is recommended.

Telephone & Internet
In some countries there are no problems while in others, Internet browsing is subject to heavy restrictions. In China, for example, common Web sites like Google and Facebook are not accessible, but other sites too could be difficult to access. The Chinese alternative to Google is Baidu. It is in Chinese only but the home page with the classic white box for searching does not require instructions.
To be able to surf freely, the only viable solution is to install a VPN program in your laptop.
Roaming is very expensive in general. If you stay for more than a few days, consider buying a local sim (very cheap, including with data traffic only).
For messaging, the alternative to WhatsApp is the excellent WeChat.