I say this all the time: you have to practice, practice, practice, to get better at writing. Keep writing, keep reading, but mostly just keep writing. Write, write, write. This skill is like a muscle. The more you exercise it, the more it will grow.
But muscle-building is not a constant process. If you push yourself to run faster, lift more, and work harder every day, you will see something weird happen. Instead of zooming into muscle proficiency, you will remain at the same level. You might find yourself slowing down, not recovering as quickly, and generally losing your mind. You're burning yourself out by working at full steam all the time.
By taking a day or two each week out of a workout schedule, you can take time to recover and come back energized.
Obviously, the writing metaphor extends to this as well. You can't write all the time. Seriously. Even if you think you can, I'm telling you: you can't. If you write all the time, you'll burn yourself out, just like in a workout. So take a break. I've talked about this before.
Now, there's a problem here. In a healthy lifestyle, working out five days and vegging the other two doesn't work. Running, swimming, whatever is no good if you spend the two break days lying on the couch, eating junk food. Yes, it's rest. Yes, you'll be able to recover. But it's not healthy.
An active lifestyle combats this with active rest. There are certainly times for lying on the couch with mountains of ice cream. However, they are balanced by actual activities. Go on a walk. Clean out your garage. Offer the ducks at the park a special interpretive dance. Get out and do something active, without pushing yourself to constantly be better. Don't run, don't swim, don't do pushups. Just be active. That's active rest.
I'm going to stretch the comparison even further. In a writing life, the same thing applies. Sitting on the couch watching movies is very passive. The story is given to you-- you don't have to imagine the characters, you don't have to think about their motivations, you just watch, and the movie gives you everything.
Reading is a little bit better. You're forced to imagine everything that's happening, interpreting the words for yourself. It's a way to refresh yourself actively. Reading, absolutely, is a great option.
But you can do something more. Active rest for writers is more than just reading. It's creating.
The muscles you use for writing are the muscles you use for creating. When you draw a picture, you exercise your visual and expressive skills. When you play music, you work on performance, structure, and making things sound perfect. When you spend thirty minutes fitting every last dish into a dishwasher, you're exercising the muscles that put words and sentences together, or that juggle ten characters in the same scene. Creation, whether it's art, home maintenance, or interpretive dancing for ducks, is active rest.
Ever notice that when your hands are moving, you can think up ideas more quickly? That's active rest. Ever notice that when you dedicate yourself to a non-writing-related project, you get more excited for your own writing? Maybe this doesn't happen to you, but it happens to me. Active rest lets you recover from the exercise of writing.
I still hold to the advice that you should write as much as possible. Write everything you can. But when you feel yourself burning out, don't push yourself past your limit. That's foolishness. Instead, take a break. But use your break wisely. Create. Imagine. Keep your mind active even during your rest.
And yes, filling out a spreadsheet counts as creative. Fixing an old clock counts as creative. Cleaning out your refrigerator counts as creative. (Hey, I'm not going to give you an excuse to procrastinate either. That thing needs cleaning and you know it.) I'm telling you that work counts as active rest. That's why writers with day jobs don't burn out as easily. You'll notice that I'm not saying that binge-watching Netflooberwhatever counts. Trust me on that.
My best advice will always be to write. If you can't write at the moment, create. You'll thank me for it.