I favor walking away and creating alternatives. Turn on, tune in, drop out! It is not necessarily required to destroy capitalism. It does a lot of that to itself. Use everything from communes to co-ops to swaps and giveaways to take energy away from capitalism. Starve it to death until it is weak enough to drown in a bathtub.
Mostly capitalism relies on making people want things. There is a very limited amount that it can force people to buy before either they revolt or they simply don't have the money to pay up no matter how much they are hurt for not having it. So it can pretty much be starved to death. Here are some ways ...
Study different economic systems so you know what you're working toward and against. If you want to replace capitalism, you need to pick a replacement. Consider your values and ethics in making this choice. Work on it until you can frame your personal economic stance in a sentence or two. Seek other people who share your perspective and goals. LOTS of people are disgusted with capitalism. It's a big driver of humanity destroying the Earth. Healthy societies, and their economic systems, do not saw off the branch they're standing on. Try to be smarter than a cartoon character.
Distinguish between wants and needs. Wants are things it's nice to have but not necessary. Needs cause negative consequences if you don't have them. Practice unwanting things. The less you want, the harder it becomes for people to manipulate you. Learn how to meet your own survival needs as much as possible.
Read about credit unions. Find a credit union.
Explore food co-ops. Find a food co-op. Learn how to start a food co-op.
Learn about community-supported agriculture. Find community-supported agriculture, farmer's markets, or U-pick farms. You can start your own CSA. You should at least know how to grow your own food.
Read about intentional communities and intentional neighboring. Find an intentional community. Learn how to start your own intentional community or sharehouse.
Explore community currencies. See a list of community currencies. Learn how to start a community currency.
Find a barter exchange network online. This list has barter and swap networks. Learn how to start a barter club.
Practice giveaways. Host a potluck instead of eating at a restaurant, and remember the history of the potlatch.
Explore sewing, knitting, and crochet. Know how to alter and repair your own clothes. The more you make and maintain, the less you have to buy as expensive finished products.
Learn about home repairs. You can fix many things yourself. Start with easy repairs.
Know how to build, repair, and upcycle furniture.
Create your own entertainment. Explore free or cheap hobbies. Learn to sing or dance. Rise Up Singing is helpful for groups. Play games that need no equipment.
Appreciate friends and family. Spend more time with them.
Practice solitude and amuse yourself alone.
Save people. It tends to create loyalty. Do it any way you like -- feed them, loan them a room, jumpstart their car -- according to your skills and resources. Model a noncapitalist way of life. Most people will try to offer you money. Decline it politely but firmly with a statement regarding your perspective on ethical economics. If they keep pushing, direct them to pay it forward instead. You will often encounter opportunities to save people, because capitalism has little or no interest in that, and it creates a lot of human wreckage. View that as an opportunity, watch for it, and be prepared to act.