The overall worst mistake is to forget that your CV is all about communicating with somebody who has no prior knowledge of you. Anything which makes your CV more difficult to read and understand is a serious mistake.
There are no hard and fast rules for CV writing, it should just be based upon common sense. Why is a two page CV preferable? Simply because that is about the amount of information a prospective employer is going to be willing to consider in making an initial assessment of any candidate.
When a prospective employer considers your CV they need to find page 1 interesting enough so that they will be encouraged to turn over. By the time they reach the bottom of page 2 they will need to have made up their mind about you. This means that you can put background information, or anything which is not relevant to the decision making process, onto a third page with no harm. This may include education as well, depending upon the level of your career.
Yet one of the biggest mistakes is based upon the idea that a CV must fit into a two page format at all costs. So, in an effort to cram all the information into this desired space, people will often use a font which is so small that it becomes really difficult to read. Really silly mistake!
Which brings me to my next point ? it is not necessary to include too much information, there will simply not be time to consider it all. So go through your CV carefully and cut down on the adjectives and anything which is repetitious ? you?ll be surprised how much that will help. Then, bearing in mind that the CV is all about you and your skills, not about how your last employers ran their business, take out any unnecessary detail and leave only the bare facts.
If you are in a technical role, then I would strongly advise that you include a technical skill set. This will make sure that all your technical skills are covered in one place. If you remember that IT is a set of tools, you can then get on with demonstrating how you have used those tools to deliver required outcomes. This will avoid the big mistake of littering your CV with numerous references to various technologies, which can make the whole thing appear confused and difficult to understand. Remember that less is more and keep it simple!
Many people believe that you need to include descriptions of personal attributes in a CV but that this is only appropriate if you also include validation of any such claims. For this reason I prefer to include AREAS OF EXPERIENCE and ACHIEVEMENTS. Thus, you can demonstrate your skills and when you have used them, rather than making exaggerated claims. After all, whilst I would be absolutely certain that everything you were saying was true, the reader can?t be expected just to take your word for it.
There are other big mistakes which people make in their CAREER HISTORY (Employment) section, most of which are errors of omission. The first is to identify previous employers by name alone. This is OK if the Company is a household name, but otherwise you may be failing to show the environment you have worked in so it will be impossible to evaluate your achievements in the role.
When you give information about your responsibilities you should give some information about how you fit in with the organisation as a whole. Say whether you have operated within a team, whether you are a team leader, who you report to, the level of your financial responsibility, and anything else which makes your work within the role unique.
Other mistakes are the inclusion of anything which is ?a given? for a particular job eg an accountant who prepares accounts. Tautology is another common error, eg saying that you are a sales manager who manages sales.
So what you should be doing is making sure that your CV is easy for a busy person to read and understand. Set the context for your employment and resist the temptation to describe yourself and your personality in glowing terms. Avoid repetition and deliver a CV which will give enough information, but not too much, so that readers can make up their own minds about you.