A resume should be written in the past tense for previous jobs and in the present tense for current positions. When crafting a resume, it's important to use the past tense to describe responsibilities and achievements from previous jobs, while the present tense should be employed for your current role. This approach ensures clarity and consistency, making it easier for potential employers to understand your career progression and current duties. By adhering to this guideline, you present a professional and polished document that effectively communicates your experience and skills.