Proper resume format is important to guide you when writing one from scratch, but you can also use resume format template if it’s more practical for you. Starting from margin, a full inch is always preferred, especially if the resume is printed by the employers. Smaller margin tends to make the resume seem clutter and chaotic too.
It may sound like a trivial thing, but don’t forget to check and edit your resume format when you’re done. Always use spell check and ask someone to edit your resume. You may have not realized it yet, but a simple typo can ruin the impression the employers already have towards you.