Answer: Revision, Peer Review, and Research
Explanation:
Revision: A good writer reviews their work when they are finished. This is helpful because, when reviewing your work, you could find spelling errors you need to fix and you could notice that you don't like the way something is written/want to add something new so you could change it.
Peer Review: A lot of good writers use peer review to help them with their work all the time. Peer review is helpful and important because (we'll use the example your writing a book) you'll get feedback from a live audience and they could tell you something you should change or add to make it more interesting for you readers. When writing something, you want your readers to enjoy what they're reading and what your writing.
Research: Research is very important, and every good writer should research before they write, unless they already feel like they know everything on what they're writing about. Research on the topic you're writing about could help you learn something new that you didn't know before and can make sure that you aren't spreading false information around. It can also help you construct and organize your writing.