Make sure you include lots of customized words straight from the job description you are applying for, this will increase the chances of your application being pulled by the computer software. For example: the job description requires a BSN and your resume spells out Bachelor of Science in Nursing....the computer doesn't recognize that you have a BSN.
PDF is a widely accepted format. Sometimes a recruiter or website will offer options, but a PDF is a good go-to format. Word is usually second to PDF.
And for $&%* sake, proof read!! A resume is usually your first presentation of yourself. Typos, mismatched formats, excess info, etc might get your resume shredded fast.
Short and sweet. Play up your strengths. Your weaknesses are simply areas on which you can grow.