One question I get frequently from job seekers is “do I really need to write a cover letter;” and, the short answer is, Yep! You do. I always advise my clients to include one, even if the application doesn’t call for it because you never know who will be reading it. Some hiring managers disregard them; others require them. You don’t want to get stuck with the one you requires a cover letter that you haven’t written. Think of it as insurance. You don’t need it until you need it.

To simplify things, I’ve come up with a list of tips for creating an effective and impressive cover letter, and have included samples from real cover letters our firm, The Career Strategy Group, wrote for real clients.

1). Thoroughly research a company and target job. Is there anyone in your network (either personal or LinkedIn) who currently works (or has worked) for this company? Reach out. Ask about working there. Find out about the company culture. This is where you’ll learn if the company is toxic or good for women and minorities or just plain stuffy. Better to know all of this before you go through those doors as a new hire, right?

2). Once you’ve done your research, have a brainstorming session about what qualities you can bring to the role and the company. (Mind maps are good here.) What unique skills and experience have you brought to previous roles? What achievements made you stand out? Use these ideas in your cover letter.

3). A cover letter is NOT a resume. You don’t want to simply repeat your work history. A cover letter should hook a recruiter or manager with a story and a convincing argument about why you are right for the job.

Sample: Not only do I know how to fortify HR for business results, but I have shaped high-performing cultures of excellence through bilingual engagement, communication, relationship building, collaboration, and mentoring. As reflected in my resume, I offer a strong dedication to service along with empathy, agility, and top integrity.

4). Keep it short. One page is perfect. That’s about 250-300 words. If you want to use an objective in the letter, keep it succinct.

Sample: My objective is an executive-level HR position with a company in need of transformational, action-oriented, and creative leadership.

5). Show how your past experience and the requirements of the job for which you’re applying are a solid match.

Sample: As a Total Rewards Specialist with 18 years of progressive HR leadership experience at Disney, Volkswagen, Target Corporation, and Walmart, my priority is to ensure the most market-competitive benefits and compensation programs while leading efforts to constantly improve employee wellness and satisfaction.

6). Highlight your strengths and unique skills.

Sample: [My] success stemmed from not only my proactive, analytical approach to process improvement but my capacity to collaborate across corporate levels and communicate to all audiences. Adapting to business needs, I can clearly convey to executive leaders the changes that need to be made and the roadmap for driving success.

Sample: I excel in aligning HR with corporate strategy, fostering a culture of trust and innovation, minimizing corporate risk exposure, and improving team dynamics in constantly changing business environments.

7). Add numbers and talk about quantifiable past achievements. Sum up your past benefit as an employee. Did you reduce costs or boost sales? Were you responsible for more efficient systems or programs?

Sample: Coordinating up to 40 cross-functional, multidisciplinary professionals in executing initiatives-on budget and on time.

Sample: Starting at Discovery, I have provided HR leadership for complex, multi-state regions. At Sam’s Club, I instilled consistency in HR and led the organization through massive change across 23 states. At REI, I built a new business strategy and structure for a multi-unit HR organization in 9 states, and at Kaiser Permanente, I created a progressive HR organization supporting 40 states.

8). Keep the tone relaxed and informal, but still professional.

9). Tell a story about yourself. Talk about your interests and what drives you. Make sure your personality comes through.

Sample: I conscientiously stay current on trends and best practices. I co-lead SHRM Compensation & Benefits Special Interest Group in Northern Virginia, and I am a guest speaker and course presenter at the HR Source.

Sample: In addition, I am an SHRM Professional in Human Resources candidate with a relentless commitment to improving the culture and elevating performance in a corporate setting.

10). Explain any gaps in your resume briefly. If you are currently not working, you can also mention this briefly, and why. Put a positive spin on it.

Sample: In 2008, an opportunity presented itself to me and I left my position as a senior paralegal to follow my husband’s career through multiple deployments and moves. I have since experienced several life changes that have made me a better person with a renewed interest in the legal field. As such, I am ready to return to the challenges of a paralegal career and am interested in joining your firm as a productive member of your legal support team.

11). End with a ‘call to action.’

Sample: I will contact you on [day] at [time] to discuss how I might add value to your team!

Sample: If these qualifications, which are further detailed in my resume, match your needs, I would welcome a personal meeting to discuss with you how I might contribute to your organization.

12). If you’re a graduate or a career changer who does not have experience in the field for which you’re applying, highlight the experience and skills that you do have.

Sample: Prior to Accenture, I had the opportunity to manage a portion of the Boston College’s endowment as a student member of the Lockheed Funds program. I gained real-world financial investment experience and exposure to equity and fixed-income valuation, financial modeling, technical analysis, and portfolio management. My resume provides further details of my credentials and qualifications. I am eager to meet in person so that I can elaborate on how my business degree in finance, Bloomberg certifications, and work experience can be of benefit to your company.

Remember: the purpose of a cover letter is to grab the interest of a recruiter or hiring manager so they will read your resume and consider you as a serious job candidate. That means that you may need to address gaps, create a call to action, and customize your resume to meet the needs of the position. Lastly, always include a cover letter, even if one isn’t requested. Keep it short. And, make it count.