How do you be very smart?

Answer 1

The best place to start is by reading. If you don't know how, find a way to learn. You can get information at a library or on line.

Just read as much as you can, starting at whatever level you are in reading skills. Just keep reading; make an effort to improve your reading skills as you go along; make an effort to read a wide variety of materials. As you are able, try to distinguish good grammar from bad grammar; not all published writing uses good grammar. Just keep reading.

If this sounds too boring, 1) you haven't looked hard enough to find what could be interesting to you, and 2) you are not suitably motivated. There is no shortcut to knowledge but only you can make use of the resources around you.