A CV has one job, and one job only.  It is a sales document that is designed to secure you an interview.  It therefore needs to be designed in such a way as to ensure that the your potential employer can find the information that they need quickly and easily.  It also needs to have impact.
 
There are a number of unwritten rules about CV writing as follows:

• Always write the CV in the 3rd person, and not the 1st person (i.e. a sentence in the CV might read:  Duties and responsibilities included…., rather than My duties and responsibilities were….).
• Always start with the most recent events first and work backwards in time (e.g. under the title of Work History, start with the most recent employer first).
• Dates should be shown as both month and year (i.e. September 1999 – January 2004, and not 1999 – 2004).  If you put down dates from 2004-2005, the employer does not know if this is a 1-month or a 2-year period of time.
• Include the following sections:
  • Personal & Contact Details
  • Work History (most recent employer first, going backwards in time).
  • Education & Qualifications (again – most recent first, going backwards in time).
  • Key skills and experience – just an objective outline of the key selling points for that candidate (optional).
  • Other Information – keep this relevant and factual.
• Avoid the following:
• Personal Profile – this tends to be subjective, and is often not relevant.  You also want to avoid giving personal information that could be misconstrued.  This can be a reason that employers will reject a candidate at interview stage (e.g. Enthusiastic football player – the employer might make the assumption that this candidate will not be available over weekends as this is when the majority of football is played).
• Don’t give irrelevant personal information.  (e.g. two children called Tom and James).  Employers are not usually interested, and again it could cause an employer to make inappropriate and sometimes discriminatory assumptions about the candidate.
• Avoid anything that could be construed as discriminatory.
• CV layout should be clear, clean and easy to read. 
• Do not clutter the document with irrelevant information.  A client will usually spend approximately 30 seconds scanning a CV, so you have very limited time to make an impact.  Use bullet points and short sentences and avoid large blocks of text as this can be off-putting to the reader.