Stop Sub-vocalizing
Sub-vocalization is the habit of saying the words in your head as you read. This limits your reading speed to your speaking speed. Practice 'visual' reading.
The Pointer Technique
Use a pen or your finger to guide your eyes across the page. It prevents your eyes from 'skipping back' (regression), which wastes 20% of your time.
Focus on Keywords
Don't read 'and', 'the', 'is'. Train your brain to pick up nouns and verbs. The meaning of the sentence remains the same.