Fast readers read and think with their intuitions. What is your language intuition, English in particular? This graph explains it well.
sSitting on top is the meaning of the text that is to be read off. To get it is to understand it (the left arch on the graph). For you to understand something, you'll have to process the text information input into your conscious. This process requires a set of neurological functions performed in your cortices. These are the biochemical processes that happen in and between the neurons facilitated by a number of substances among which are neurotransmitters such as dopamine, GABA, and endorphin.
You need a basic level of such substances to understand the easy texts whose structure is simple and meaning explicit, but it will take you a lot more if text structure becomes complex and meaning in-explicit. The question is not how much neurotransmitters you should prepare for yourself — you can by no means manage the exact amount. The question is how you prepare (or produce) more when you need them?
Your hypothalamus knows how to and produces them for you, and you just need to tell the hypo to bring it up at times especially when facing hard, in-explicit text. This message is constructed in the form of an complex emotion that is typically a product of your subjective feeling of your own success rate in understanding that text. When you feel positive of your efforts, a complacency emotion tells your hypo to bring up the neurotransmitters. The more the neurotransmitters, the faster you are to understand the text. On the contrary, any negative feeling of yourself tells the hypo not to produce more neurotransmitters. Moving on, as the transmitters are consumed, you have diminishing chances to understand the text.
This complacent emotion, is your language intuition (the element sitting on bottom of the graph). It is generally built through years of reading experience, ideally on a variety of subjects and genres. That is the case for a natural good reader. However, you are not doomed if you are not already one of them. Intuition can also be built through systematic but quick training. This generally consists a number of ways to reproduce texts (right arch on the graph) from good sources. One of most effective technique I use is to read loud and fast, some times to recite the entire passage by memory. Being able to reproduce the text drives the intuition, thus creates a complacency before even understanding the text. In reality of reading, text reproduction indeed happens unnoticeably in your cortices and signals the hypo for more neurotransmitters.
Thus, reproduction, intuition, understanding, and meaning forms a full cycle of neurological process of reading. The key in building or breaking this cycle, a factor that can be proactively controlled by yourself, lies in the ability to reproduce the text.