Well, practice is the thing, but, you have to practice speed reading, not just reading. Did that make any sense at all
You have to learn a new way of reading that is not just about speed. You should be able to find a lot of help on this without buying anything, and I think that it's part instruction, and part talent. In other words, some people just can't read as fast as others.
Ok, I just put in a personal example, but it was way too long IMO.
Start with tracing the words with a pencil or your finger. Move it faster than you like to read, and try to keep up with it. The point is to force your eyes to keep moving on to the next word.
Most people move on to tracing a line straight down the page instead of across each line. After that is up to you. You want to be able to take in groups or even whole lines at once. I can usually do this by paragraph if required. I wouldn't be able to repeat it to you, but I know what it was saying.
That reminds me of another trick. You aren't reading every word. Pick out the "important" words. Think of it kind of like using a high-lighter. Most of the paragraph is just words supporting the concept be expressed right?
I hope this helps. I can try more if you'd like. I haven't actually analyzed what I do in years, it's just become second nature.