Friends is fine
Family is fine
Talking in online games is fan
Stranger... Critical error...
Confidence is key.
How are you when speaking to strangers in dutch? Obviously you know your words, but would you say you can just jump straight into a conversation, or are you still nervous?
Is there an English/MFL club at your school? Getting to speak with strangers and practice roleplays is good.
Obviously when you're ordering at a restaurant or a bar, or meeting someone new, you say different things compared to chatting with friends/family.
Ultimately, it still just comes down to practice.