How do I show that I have a strong ability to multitask on my resume?

In this fast-paced society, everyone has had to juggle multiple tasks simultaneously.

In order to reveal this skill-set on your resume, it is important to identify the project(s) and specific actions that you took, and the result of that effort.  Or perhaps there were multiple concurrent accomplishments that you completed in a timely manner.  Whether you have a high-volume workload, managed multiple short-term deadlines, or interacted with more than one supervisor with diverse requirements, there are ways to properly express this on the resume.  If you are re-entering the workforce, after a period of time, it is easy to demonstrate how juggling responsibilities at home are of value to the job.  As a student just entering the workforce, showing how you balanced academic responsibilities for multiple class assignments is equally valuable.  We all have examples of multitasking.

First, it is important to review the job description to determine if there are any specific requirements for multitasking skills.  If so, try to include those Key words or phrases on your document.  Where appropriate, under your Job Experience, include one or two bullets that reveal this specific skill-set, as follows:
As Administrative Assistant to two SVP’s responded to hundreds of emails, while answering incoming calls and scheduling board meetings.
Responsible for multiple client accounts while supervising a team of 15 interns.
Organized a Seminar with 200 participants; developed and distributed the agenda; marketed the event; retained the speakers and sponsors; generated $25,000 in revenue.
With each example, if appropriate, you might include that you received high praise for the completed tasks, received promotions, or solved a problem.  This will demonstrate that you managed multiple assignments with ease and were rewarded for your efforts.  Multitasking is not a skill that requires extensive repetition on the resume; however, including one or two examples, or bullets on the Skills List, will show the hiring manager that you fulfill this requirement.