You don't need to go shouting it, but if someone starts talking politics at you, fucking own it. Some coworker is like "trump sucks", say "yeah I know, I'm a communist". Your grandpa says "trump rules", say "no he sucks ass, I'm a communist". You're on a date and they ask who you're voting for? Say "I'm a communist". Cashier asks would you like change? "Yes, I am a communist".
Be open about your politics and lay claim to the title. Be a communist.
meeting them at their beliefs is absolutely the way to go. If you start off with "im communist" you're immediately on the defensive footing, having to defend your position while they mouth off over a century of propaganda. If you're new to talking about that stuff that might be fun, but after hearing "muh animal farm," "human nature," and "100 gorillion dead" you get really fucking tired of debunking it. If you engage them with the things they believe in, and then bring them out to their logical conclusions, you will have MUCH more success.
Radicalizing people isn't immediate, but you're most successful when you explain how the issues people care about all end up pointing back to the failures of capitalism. It's not a one time thing either. When people ask about what you believe in, be open about it. When they ask good faith questions, answer them to the best of your ability. It's ok to say that you don't know - but then you should go find out and learn so that you get a better understanding, and are able to explain it the next time you see that question.
Most people can sense something is wrong with the way the world is. The only answers to why are given by communism and fascism, and one is obviously superior to the other.
However, If someone is engaging in bad faith argument and just trying to waste your time, or trying to say that you're a communist so they can go "muh look at crazy commie!!!!", then just send them pig poop balls and dunk on them until you're bored or they go away.