can you really teach yourself to be smarter?

Sure, it's never too late to learn something new.

The best way that I have found is to read. Read every day, it will expand your vocabulary and improve your spelling skills. I would not tend to believe the scams they try to sell you in book though, it is nothing you cannot accomplish on your own.

I wouldn't say you can necessarily teach yourself to be smarter, but you can improve skills you might already have or be lacking in. If you push yourself harder, you will see great results in a matter of time and you might find yourself learning more.

Anyone can improve their intelligence. I don't think you need a book to tell you how to get smarter though, you just do it on your own.

your mistakes teach you to be smarter.