What is the best way to get a chinese tourist visa?

Hether, one month before your travel, you can submit the application for a mainland PRC entry permit to the embassy in Hanoi. You may need to submit your passport, a photocopy of the passport's data page, a filled-out application form attached with your recently-taken color bare-headed photo, the original and photocopy of your work permit in Vietnam, and an invitation letter from your friend. It's not suggested to apply from Hong Kong or Macau as the process might be harder if you apply from there.