1. Self-Review First
Always diff your own code before submitting a Pull Request. You'll often spot debug statements (console.log), trailing whitespace, or commented-out code that shouldn't be committed.
2. Focus on "Why", not just "What"
The diff shows what changed. Good commit messages and code comments should explain why it changed.
3. Watch for Whitespace
If a diff shows the entire file as changed, you might have changed the indentation (e.g., tabs to spaces). Use the "Ignore Whitespace" option to see the actual code changes.