Good writing is clear and concise. Word choice matters. You should use strong words and choose them with confidence. That requires rich and ample vocabulary and knowledge of the pros and cons of adjectives and adverbs. They can hurt the meaning of a word they modify. It makes text weaker and harder to read.
You can expand your vocabulary by reading a lot and learning new words. It is vital for non-native speakers but also beneficial for everyone who wants to improve their writing. But finding the right words could be hard. Sometimes you know what you want to say cannot come up with a good word for that.
Solving this problem for myself, I found "Reversed Dictionary". It is a search engine for words. Standard dictionaries and thesauruses are helpful only if you know the word already and want to learn or verify its meaning. With Reversed Dictionary, you put what you want to say and it gives you back words that could fit.
For example, you want to say that "someone walks slowly". "To walk slowly" is a verb + adverb. You may want to change it to one word only but don't know such a word. For example, you can use "to shamble" or "to stroll" to say the same as "to walk slowly" but make the text brighter and stronger. Same works for "to eat quickly" ~ "to scoff", or "to read quickly" ~ "to skim". These are basic examples and their usage depends on context but the idea should be clear.
I've been using Reversed Dictionary only for one day and already found it valuable. I see it as a great approach to improve writing and learn new words. This tool boosted my long-standing interest in NLP and I'm going to research this topic more.
P.S. Another amazing resource is Vocabulary.com. I pair it with Reversed Dictionary to discover new words and then save and learn them.