The best way to unionize is to follow what Mahatma Gandhi did: Non-cooperation movement.
It consists of two broad strategies:
1. Consumer Non-Cooperation (Boycott): Boycott of stuff sold, or given by these companies, irrespective of how attractive it is.
2. The Constructive Program (Self-Reliance): Building and supporting alternatives, even if they cost you a little bit more.
All it needs is little self-discipline and a very very tiny bit of sacrifice on daily basis.
https://www.nextias.com/blog/non-cooperation-movement/