To write an ATS-friendly resume, use keywords from the job description, choose a simple format with standard fonts, and use bullet points for easy scanning. Include relevant sections like contact information, summary, work experience, education, skills, and certifications. Avoid spelling errors, images, and complex designs. Tailor your resume for each job, use active voice, and quantify achievements. Optimize for length, aiming for one to two pages. This ensures your resume passes ATS filters and impresses recruiters.