Most prominently, just by doing it.
People seem to think just because you write every day means you can write prose without trying or practice. Like just because you speak every day you can absolutely make moving speeches without practice? Sure. No. Writing a is a craft and a skill as much as anything else. You want to get better at it, you've got to do it. And to be honest, you can look at a lot of more prolific writers first novels and they're just not as good. There's a reason "bad first novel" is a thing. You've got to just practice and get through the phase of being bad before you get to being good. Like playing an instrument.
Reading things out loud also helps a lot. Is it easy to say? Is it easy to read? Try to read it with as little emotion as possible and see if it still evokes emotion without you putting it into your voice. Does it feel natural?
And beyond just practice:
Read more is so so advice. You should generally read things in similar genres to you, because you'll see what other people in your genre are doing and what conventions are. However just read more isn't really about things like them describing the same thing as you, it's analysing the text. What are they doing that makes you feel? What are they doing that makes you imagine? Things like the flow of sentences. It's just your basic lit class stuff.
Never try to imitate someone else's work unless you're specifically trying to imitate someone. For instance, if you're writing a Sherlock Holmes spoof, then it's important to understand what makes Sherlock Holmes Sherlock Holmes. But if you're trying to write your own work, write your own way.
Purple prose is not all that hard to avoid. Just don't take several pages to describe how beautiful a field is when a sentence would do. Some genres can get away with it and some instances where you want a character to get poetic or to set atmosphere, it can work, but generally, don't be excessive, it's that simple. A lot of the time, just being simple does the job.
Also general writing advice channels on places like youtube have a lot of good tips. Jenna Moreci is one of the better ones with a lot of good tips you can apply pretty easily.