I was taught this saying many moons ago during my years of traditional grade schooling. Yet, it is still true for me today that reading is a great source of both entertainment, ideas, and a way to observe the writing styles of others. I would even suggest that reading best-sellers are one of the best ways you can notice what makes a book a best seller for yourself.
So what can you do if you don't have time to read? It's understandable, for whatever reason, you may not have a few hours to sit down with a book. This is why I often prefer to use audiobooks during the school year. However, I haven't been the best at writing down the things I like and don't like from different authors. This is where reading becomes the most useful to you as a writer.
Some writers closely follow the model of the hero's journey, others deviate from it quite a bit. Looking for why is important! Look at why or why not the author's chosen writing model kept your attention. How could you implement something similar for your own work? Another thing to consider would be if you even know what the hero's journey is, and where it classically has shown up over time.
What else could you learn from reading the work of other authors? We could analyze theme, tone, plot, character development, backstory, climax and a host of other literary elements. Why would you want to do this? I promise that literary analysis isn't intended to take the fun away from reading a good book at all! Its purpose is to get you to slow down enough to read between the lines, to really think about what you are reading.
Keeping a record of your literary analysis notes will be huge in inspiring your own writing to become better. I had to analyze a few books in school a while back, at first, I will admit I didn't really like doing it. However, as I started to see real things that I liked, things that made a book stand out, I also saw that I needed to impliment these kind of elements into my own work.
Reading allows us to gain perspective and greater vocabulary as writers too. We gain real experience with another authors ideas though physical and tangible pages! Isn't that alone motivation enough? A lot of work goes into having a published work of literature! It isn't easy by any means, the challenge seems to still be my call to adventure.