A lot of places around the world call it A Curriculum Vitae, in North America, it's a Résumé. This is definitely one of the most important tools that any jobseeker has at their disposal. You may be THE best candidate for a particular job by a long way, however, if you don't make it to the interview stages the company will never know.
Many companies (especially the larger corporations) will use computer software to "read" all the résumé’s and reject any that don't fit a particular template. This may seem unfair, but it's cost effective.
So, for some jobs you have to beat the computer and still read well enough for someone who may not have any knowledge of the position you are applying for. It is definitely worthwhile to adapt your resume for the position that is advertised. There may well be some of the "buzz" words the "filter" is looking for mentioned in the job description.
It is very important that you can substantiate all the claims you make, preferably with physical examples or letters. This will be essential in any in interview situation.
There is now a wealth of information available online, from books, local employment offices and with professional writing agencies. You can also access other people’s résumé’s that are posted online which will give some great ideas for style and content.
Professional writers may seem the answer, but, all the research I have done seems to lean away from them. I have never used one and feel that it will give a good impression if you have written it yourself (this will display literacy). Apparently, if they are professionally written, they are easy to spot; however, they may be worth the expense if you are stuck. You can always "customise" what has been written to make it your own work.
In my case, I had been in the military since I left school and had never written a resume or had an interview. I spent a lot of time writing, copying other people’s styles and changing things. I didn't realise how difficult it is to catch up on 16 years - I'll never allow mine to go out of date again! I found the hardest part was to actually start writing. The best advice I was given was to just write anything that you can think of and it will soon start to flow. With modern word processors it's relatively quick and easy to cut and paste so you can keep on changing it until you are happy. More detailed information can be found at http://www.onestopimmigration-canada.com/resume.html