When you are looking for a job, your resume and cover letter are your chance to tell your story, to set yourself apart as a real human being, not just another faceless applicant. The goal is to let the hiring person see if you will be a good fit for their company and position so they know whether or not they should call you for an interview. Canned language hides your personality and makes it harder for them to see the fit.
Before starting the lists of work experience and skills, think through your story. How did you get where you are now? What motivated you? Why do you want to work for this company? (Hopefully there is a reason beyond getting a paycheck: you love their product, you’ve heard good things about how they treat their employees, the work interests you.) What makes you the right person for them to hire?
Is there anything in your work history that you need to explain? If you have been out of the workplace for a while, why? Were you taking care of a dying relative? That could say something about your compassion and ability to advocate for others. Are you changing careers? Show how your prior experience led you to the change, and what skills transfer. At a minimum, work habits and communication skills will always transfer.
Remember that there is more than one way to accurately tell a story, and choose the version that is kindest to you. Don’t lie, don’t even stretch the truth. Just tell the story as your mother or doting younger sister would tell it, with the positive things left in; listing real qualifications is not bragging. Ten jobs in five years doesn’t necessarily mean that you are flighty and unreliable; it might equally mean that you have an active curiosity about different jobs or that you have high standards and are unwilling to settle for a job that doesn’t fit – but now you know what does fit you and are prepared to stay in one job. Only you will know what rings true for you, and what you can defend (with a straight face) in an interview, but find a way to tell the story in a positive light whenever possible.
Once you know what story you are trying to tell, choose the resume tools that best communicate the story. Make sure your cover letter spells it out, concisely. The more you can get across your story, the better feel a potential employer will have for you and how you can contribute to their business. If you don’t get called for an interview, it may very well be that the fit isn’t right; for instance, you prefer structure and the company is very relaxed, or vice-versa.
Always have someone else look at your resume and cover letter before you submit them, preferably someone who knows you well and won’t be afraid to tell you what they see. It may be completely different than the story you tried to tell!