Becoming a great sight-reader is no different than becoming a great reader of a particular written language, such as English or Mandarin. You become a great sight-reader by exposing your brain to a wide variety of written music. The Internet makes it easier to become a proficient sight-reader because there is so much music online available for free.
Another resource for sheet music is MuseScore.com. Unfortunately, you can no longer download MuseScore.com scores for free: you have to buy a Pro membership for the download option to be available to you. If the price of MuseScore Pro is within your budget, it is a great resource for downloadable music scores. In this article, I'll explain how I use MuseScore.com scores to help build my musical brain.
Step 1: Setting and Achieving Goals
My musical goal: every day, I want to expose my brain to a piece of written music that I have never seen before.
My methodology: Each day I go onto MuseScore.com, and I do a random search for sheet music. When I find something interesting, I'll download it, and I'll then open it in MuseScore on my local computer. I'll then add an alto saxophone part to the music, if it does not already exist. Then, I'll copy the melody of the song to the alto saxophone part, so that I can play it. After I play the song in one key, I'll often use MuseScore to tranpose it into one or more other keys so I get to feel how to play the song in multiple keys.
Step 2: Develop the Discipline to Make This a Way of Life: Do it Every Day
This is REALLY the hard part. It is easy to do this routine for one day, or even for one week. What is hard is to do it for 1 year, 2 years, 15 years, or best of all, for an entire lifetime. Life makes it so hard to focus on one thing because it throws so much noise AND signal at us, that it is difficult to separate the signal from the noise. Ultimately, it comes down to making a choice: each musician has to make a choice between being constantly focused, or constantly distracted.
One tool that I've found that helps to keep me focused is a journal. A journal does not lie: if you make an entry one day, and then skip 7 days, then it is clear that you are not really focused on the task at hand. So my recommendation is that you start a saxophone practice journal, and that you make a pledge to yourself to make at least one entry in the journal every day. Make the journal as simple as possible: mine is a simple text file on my computer. The simpler you make it, the greater the chance that you'll remain committed to using the journal to continuously improve.