My answer is a little different.
Of course you have to speak to improve speaking.
BUT...
You should read and write as well.
I know it sounds strange. But when you read you learn how the words all go together. You learn idioms and phrases. It helps your mind get the order and feel for the language.
Writing helps your mind put these new words into practice at a slower speed. Your speed.
Speaking can then follow and improve.
In my experience, people who read and write learn faster than those who do not.
You can find lots of reading at
http://www.jamaby.com
and writing ... well I think you have the idea.
