Spelling mistakes: It is a proven fact that around 50% of CVs contain spelling mistakes. This easy mistake will make you seem careless and could also distract the reader's attention from the content. It may be worth considering asking a family member or a friend to read your CV and check for mistakes.
Jargon: When writing your CV you may believe that using industry-specific jargon is a good idea and that the person reading your CV will understand it but using acronyms without explaining them can be confusing to the reader and may deter someone who is not familiar with them.
Qualifications: A common mistake in a CV is to detail all your academic history - even from 10-20 years ago whilst also listing all your grades! This is not necessary. On a graduate CV or someone with limited employment history it may be useful, but for others, just briefly cover your qualifications - detailing your most recent achievement and list older ones. If you have vast employment experience spanning many years, the chances are a recruiter will not even read your qualifications.
Employment: When compiling your employment history there is no need to provide the address of your employer - all you need is the company name, your job title and the date you started and finished employment with them. Then, you can talk about your duties and achievements in each position.
Hobbies: Your CV is a personal sales tool. Any available space on a CV is limited and you want to use it to sell your skills and experience effectively. Everyone likes reading, listening to music, keeping fit and socialising with friends, so unless you have done something special - and relevant to the job you are applying for - leave it out!
Too many pages: All too often, employers will receive CVs that are too long! A good CV should be no more than around 2-3 pages (for graduate or more executive positions this may vary). The more there is to read, the less likely it is that all your skills and qualities will be noticed. Try to decipher between what information is relevant to the job you're applying for and what is not.
Unnecessary information: As stressed in the facts above - when compiling your CV, try to keep all the information relevant to the job you are applying for. Unnecessary information will take up much needed space which can otherwise be used to help persuade the reader to continue with your application. Another common mistake people make when writing their CV is including their reason behind leaving previous jobs. Examples of these can be, "I got bored" or "I didn't get on with the Manager". Obviously, this is not necessary, will make you look negative and will decrease your chances of being included on the shortlist.