How do you actually get better at writing?
Through a small number of practices that reliably work, and they are less appealing than the advice people usually seek.
Read closely, not just widely. Reading a great deal helps by exposure, but the step most people skip is noticing how something was done. When a passage works, stop and ask why — the sentence rhythm, where the information was placed, what was left out. Reading as a writer means reading slowly enough to see construction.
Write regularly, and finish things. Volume matters, and finishing matters more than starting. An unfinished draft teaches you about openings; a finished one teaches you about structure, endings and the difficult middle where most writing fails.
Revise properly, which is where the improvement actually happens. First drafts are for getting the material out. The skill is in what follows, and the most valuable habits are:
Cut. Almost every draft improves at 10–20% shorter. Look for restatement, throat-clearing openings, hedging, and adverbs propping up weak verbs.
Separate the passes. Structure first, then paragraphs, then sentences, then proofreading. Trying to do all at once means fixing sentences you will delete.
Leave time between writing and revising. Editing your own work immediately is nearly impossible, because you still read what you meant. A day's gap makes the gaps visible.
Read it aloud. The single most effective revision technique. Awkward rhythm, run-on sentences, repetition and unclear pronouns become obvious when spoken.
Get genuine feedback, which means readers willing to say what confused them. Note that readers are reliable about where they got lost and unreliable about why or how to fix it — take the location seriously and the prescription lightly.
Imitate deliberately. Copying a writer's structure or rhythm as an exercise is a long-established way to learn, and the imitation drops away as your own habits form.
Study grammar enough to break rules deliberately rather than accidentally.
Write for a specific reader, which resolves most questions about tone and detail.