Read this practice passage: "Nora lent Sam her camera. He returned it on Monday, but she had already left for work." Here, "he" refers to Sam, "it" to the camera, and "she" to Nora. Tracking those links is necessary to understand who did what.
Do not assume the nearest noun is always the reference. Meaning and grammar work together. In "The camera was in its case, and Sam carried it carefully," context suggests that "it" refers to the camera, although the writer might need more precision.
Recognize a real ambiguity
Consider, "Nora called Lina after she finished the report." Without more context, "she" could refer to either person. A careful reader should notice the uncertainty instead of inventing a definite answer.
Rewrite the sentence twice: "After finishing the report, Nora called Lina" and "Nora called Lina after Lina finished the report." The different wording makes the intended sequence and person clearer.
During reading practice, draw a small arrow from each pronoun to its likely reference. Mark doubtful links with a question mark and examine the surrounding sentences. For your own writing, replace a pronoun with a name or noun when the reader would otherwise have to guess. The goal is clear relationships, not avoiding pronouns altogether or repeating every name in every sentence.