I've learned a lot from books on the craft of writing. But I've learned the most, by far, from a 165-page book: Steering the Craft: Exercises and Discussions on Story Writing for the Lone Navigator or the Mutinous Crew, by Ursula K. Le Guin. Specifically helpful to me were Chapters 3 & 6.
Chapter 3, "Sentence Length and Complex Syntax," was a corrective. I tend to write long, complex sentences. But there's a place for a string of short, choppy sentences. The exercise directs you to write a narrative paragraph using sentences of seven or fewer words. I'd tell you what the result is, but then you won't do it and find out for yourself. But I guarantee that when you get four or five sentences down, you'll recognize the effect and someplace you've heard it used before.
Chapter 6, "Subject, Pronoun, & Verb," has an exercise called "The Old Woman," that is well worth doing in all variations of person and verb tense. I was amazed at the effects achieved by using one tense for the old woman's actions "now," and using another tense for actions she is remembering. If you write, you've heard the rule "Don't change verb tenses." This exercise shows you that you can, you should, and when and why.
I am now much more aware of sentence length and verb tense changes in my reading. This is at least half of the value of the exercises. You benefit so much more from reading other writers when you are aware of their technique.
I noticed a whole string of changes in verb tense on the first two pages of John Steinbeck's The Pearl. Nearly every sentence has a different tense. Finally, on p. 3, the book settles into a past tense narrative. A lot of the originality and magic of the book is due to Steinbeck's manipulation of verb tenses. Read it again and see if you agree.