You should gather together all of the information required below. You will probably not use all of this information in your CV but it will provide you with useful reference material when it comes to preparing for interviews.
Your full name, address, email, home telephone number, marital status (put only single or married down on your CV, if you are divorced then put single, if you are separated you are still married - never list any sort of failure on a CV) and nationality (you may want to include this if you are applying for jobs abroad or if you are a British/EU national and your name does not sound British). Do you have a full driving licence? Is it clean?
List your qualifications and education history, for example:
If you have a degree you probably will not need to list all your O Levels/GCSEs; just listing the number is probably sufficient.
List your professional qualifications, membership of professional associations and professional ID numbers. If you recently completed a college or university degree or HND or Diploma, etc, then you may want to list the courses you studied if the subject you studied was relevant to your target job.
List any work related training courses which you attended, including company courses and any you attended on your own initiative. If you obtained a qualification on any course please list it. You only need to list the important courses you attended; no one really cares if you went on a time management course as everyone gets sent on these courses!
If you have been working for a number of years you probably do not need to include any part-time jobs, vacation jobs, voluntary work or unpaid work experience. Charity work could be included in your interests. However you might want to include these jobs if they covered a period of unemployment, or a time when you were not working for any other reason, or you feel that some of the experience you gained will be useful in your next job. You should normally concentrate on your two most recent jobs (unless you were only there for a short time), because employers are usually most interested in these.
Start with your most recent or last job and work backwards. For each position (treat internal promotion as a new job and record the dates separately) list your job title (e.g. Manager, Supervisor, etc), the job title of the person you reported to (e.g. Director, Manager, etc) and when you started and finished in each job. Give the name of the company and include a brief description of the service they provide (using the terms they would use to describe themselves). Set out your main responsibilities, achievements, duties, and skills that could be transferred to another employer. Be specific and positive about your skills, e.g. 'good written skills' may be a better description of your abilities rather than 'good communication skills'. Include your level of responsibility if any, e.g. 'responsibility for departmental budget of £100K and managed 10 staff'. In particular list any achievements you had in each position, including increases in sales/productivity and cost savings made. Quantify your achievements if possible. 'Increased sales by £100K' is more interesting and positive than just saying 'Increased sales'. You should try to include some achievements such as meeting deadlines, budgets, etc, and any information that may be relevant to your next job.