As a single person, most of it comes down to what you support, avoid consuming things that rely on cruelty and slavery to be produced, study to be more aware of what is actually happening, and don't panic, there's very little a person alone can do.

Joining groups with similar minds can help you make more, but groups can be very hard, people have different views on things, and radicalism can make some good willed people do pretty terrible things.