it somewhat depends on the context of the specific situation someone is in but in broad strokes: prefigurative politics. Build mutual aid networks and forms of horizontal organization to improve the material conditions of your community - basically build the types of things that will exist in an anarchic society. To the best that one can, act like one is already living in a free society.
Do all this to decrease yours and your community's dependence on the state and capital - cooperate with others trying to do the same - until we reach the point when we no longer need it. Eventually, if enough people do this, the state will likely crack down with violence and when that day comes will we need to be ready to defend ourselves.
Different anarchists have different ideas for how exactly revolutionary change will play out. Some, such as syndicalists, believe in the power of utilising unions to bring about an anarchic society - by joining and building unions that have the explicit goal of bringing down the state and capital. Personally, I think that while this was an effective strategy in the 20th century (it worked for catalonia) it's a little outdated in the modern economy. Though I don't think unions are a complete dead end.
Overall though I think a wide range of tactics would be needed to bring about this level of change. There's not going to be any step by step plan or one size fits all solution - and you should be weary of anyone who tries to propose those things as "implementing" a step by step plan will never bring about anarchy as it will be fundamentally authoritarian.