Code reviews are about improving code, not showing expertise. Focus on logic and architecture—the team owns the code, not you. Questions teach better than corrections: "What happens if X?" is better than "Fix this."
Prioritize: critical issues, important issues, suggestions. Use conventional comments: nit: for small suggestions, optional: for preferences, question: for understanding. Follow up discussion in chat, not the PR.
The author helps: keep PRs small, context in the description, tests passing. Good reviews build culture—encourage, thank, discuss.