This is a great question and I'm looking forward to the answers. I've also wondered about how a vanguard party forms from within an empire.
obv we can't copy their tactics and strategies 1:1
As long as you keep this in mind - ARAK, "Activist Study - Araling Aktibista" has what you need.
Thank you!
The answer to your question could be pieced from several history books of different Vanguard parties(Cuba, USSR, China, Vietnam, et all). A good starting point to investigate will be to check Prolewiki for book sources containing historical information on each movement.
As for the USSR, this book could help you:
It won't have the answer in the first page but you could probably find clues there.
Thank you!
https://www.marxists.org/archive/lenin/works/1902/sep/00.htm "A Letter to a Comrade on Our Organisational Tasks"
Thank you!
Read about the 26th of July Movement in Cuba.
Thank you!
Super important topic, one that I'm still learning as well. To chirm in, all tactics and strategies should arise from the principle of Democratic Centralism. Even something innocuous looking like writing and distributing a newspaper could be an important step into organising a vanguard party.
A place to ask questions of Lemmygrad's best and brightest