Your resume is the first thing a recruiter or hiring manager sees, and is a direct reflection of not just your experience, but your attention to detail and written communication. If you even want the chance to get through the door, you want to make sure it is perfect! You should also always look at your resume like a contract, anything that is wrong in terms of schooling, employment dates, etc. can be a reason why you do not receive an offer. Ensure that everything is clear so nothing can be misconstrued.
Content: make sure it is clear and concise and tenses are being used properly
Formatting: Ensure your formatting is consistent, including spacing, use of periods, and font
Dates of Employment: Use months and years for your dates, and ensure months are spelled out
Details: Triple check for typos, including spelling, punctuation, grammar, and dates
Length: Try to keep it to one page but no more than two pages, and make sure your most recent role contains the most content