Originally Posted by Alcoremortis
I'd actually suggest reading children's books (not necessarily the illustrated kind. Could be short novels). If you've got gaps in words that you should know then it's a good way to correct that because you've got all the time you need to look up that word. And since it's fiction, it's likely that those same words will show up multiple times within the story so you'll get a bit of practice in.
If you're not a reader, picking an interesting show to watch in English would be a good second option.
I second the idea of trying children's books.
Perhaps try books you've already read in your native tongue, so that you can get the general gist of the story. That'll help you puzzle out the meaning of words on your own. I'd say the Harry Potter books might be worth a try, seeing as each book becomes more complex than the previous one, which may help you build up your language skills.