Research by Erica Chenoweth, political scientist at Harvard shows that non-violent protests that are able to actively engage 3.5% of the population always succeed. These protests can take the form of general strikes, consumer boycotts etc. Since they’re non-violent they are able to engage a broader demographic.
The researchers reviewed social movements from 1900 to 2006. The movements were considered a success if they were able to achieve their goals within a year of their peak engagement. They also applied a strict non-violence test (India’s independence movement, for example couldn’t be considered). Some examples were: