Everything you include in your CV has one purpose — to position you for the role. You need to think strategically when deciding what to include. Is it relevant to the hiring company's needs? Does it bolster your application?
Put your reader first
Once you know what the company is looking for, it's much easier to decide what to include or leave out. CVs with impact are those which tie in what you offer to what the company requires. Your offer can encompass different aspects of your background — achievements, skills, employment history, and so on — but focus it on the hirer's needs by pruning out the less relevant parts of your background.
Work out what to highlight
Company and sector research and the wording of the job ad should help you identify what the company wants from an ideal candidate. Address these key requirements in prominent places in your CV — in your professional profile/career summary and in the skills and work experience sections.
As different roles have different requirements, your CV shouldn't be identical for each job you apply for. And when applying for more senior positions, your CV should also reflect different priorities regarding skills and career achievements.
Include examples that communicate your brand
Discovering what makes you unique enables you to differentiate yourself from other (equally well-qualified) candidates. Your brand is the combination of qualities, skills, achievements and values that you can offer and you should aim to reinforce this image throughout your CV with supporting examples.
For instance, if you've identified that your ability to make difficult subjects accessible to a wider audience makes you an excellent editor, show how you've done this, and what the results were. For example: "Edited a series of highly-complex technical manuals for a non-expert audience. Acclaimed for its accessibility and clarity, this series is now a market leader, selling over one million copies".
Include enough examples of your achievements to prove your value. The more relevant they are to the employer, the more impact they will have.
Deciding what to leave off
Keep an eye on the length of your CV. If it goes beyond two pages, it's probably too long. Don't make your CV look cramped by squeezing in information, instead decide what's relevant and edit or merge the rest. Can you group similar jobs by heading (useful if you've had a number of temporary agency roles) or reduce old or irrelevant career history to a few lines of notable achievements? Would highlighting your promotions rather than listing every responsibility for each position have greater impact?
The following information can almost always be deleted:
Interests and hobbies. If you've achieved something noteworthy or relevant pursuing an interest, slot it in somewhere else in your CV or put it in your covering letter.
"No-no" details such as date of birth, marital status, religion.
Superfluous information such as driving licence, references, school grades.
Irrelevant information that blurs the focus of your CV, such as very old or temporary jobs.
Remove negative information
You don't have to explain why you left previous jobs or mention health problems. Remember that anything you include may be discussed at interview, so consider which jobs you can safely leave off — perhaps those you hated or where you didn't get on with the boss.