I think just reading a lot would be the best answer. I suggest reading all different kinds of writing (signs, fiction books, articles) in order to be familiar with different words. Knowing many words should increases speed.
Have you ever noticed the reason why you cannot read fluently as you expect? I guess there are several problems you might address:
1st: You do not have enough vocabulary to empower your reading
2nd: You do not have good logical organization ability while you are reading
3rd: You are not proficient in interpreting words to get the gist of a sentence
Any one problem above can result in your retardation in reading. You may click me if you like to practice reading altogether.