Read everyday if you’re able too! Reading helped me tremendously with my vocabulary. Read harder books as you go along. Maybe some classic English literature. Or you can always find translated books from other languages in the library.
There’s even websites online that help you increase your words read per minute. They flash at you one word at a time increasingly getting faster. Now I’m a super quick reader and I still can absorb all the information I’ve read.
Debate with others about current events, ethics, whatever
Maybe learn about philosophy? Or something you’re interested in. Could be science could be music.
For university lectures you are allowed to sit in on them for free. You don’t get a degree but you get knowledge that usually you’d have to pay for.
Being artistically creative always helps. Even if you hate it, pushing yourself to do that can help you. You don’t need to show anyone, and if you don’t like it you can throw it away.
But try and create something that’s your own like painting or poetry or cutting out magazines and making collages or making things out of clay.
Always have an open mind and be willing to change your opinion.
Try and debate others if you can. It helps all my friends are politically active so we almost always talk exclusively about what’s going on in the world.
Think outside the box. There is a lot of stuff people choose to believe because they’re told to. Understand that you were probably lied to quite a lot in school. Find your own methods of gaining information, whether that’s a friend, colleague, mentor or news site.
If you’re thinking about something and you don’t know the answer, google it! It’s fast and then you know for future reference.
Learn a language if you have the motivation! It’s useful in life, could help you get a job, and also you can make more friends once you learn other languages. Friends you wouldn’t make without knowing their mother tongue.
Some freaks would say do some math equations but I would never do that because I love myself and value my sanity, lol. Math gives me panic attacks.
Just remember that IQ smart is not necessarily equal to smart smart. Standardized testing is ■■■■■■■■. If you come from the west I should tell you that in school they prepare you to be a good test taker. Not use real life knowledge that would help you. They see you as a number instead of a valued human being.