Answer: Sentences 6 and 7.
Throughout the passage, everything rolls smoothly. The punctuation marks are used correctly, and conjunctions are used only when needed. Howevr we reach a bland sentence, "I learned how to focus my camera." Imagine you getting out of school, and your parents asked How was your day? You may respond with It was good. ok...what else, what happened that made it good. Yes, most of us may respond with this because you don't want to dive into the crazy, stressful, test filled day you had, but in stories and in the real world responding with a one noun and verb doesn't help you through anything. If sentence 7, "I also learned how to choose what to photograph." was joined with sentence 6, it would eliminate useless words and avoids any abrubt pauses in your work. The sentence then should say, "I learned how to focus my camera, as well as what to photograph." Now your reader can connect the dots easier and it's not a manual job needed to be done. Hope I helped!