Your resume is a portrayal of yourself.
It is the first - and often the only thing potential employers and recruiters look at when they are deciding who to employ.
If you have a poorly assembled resume then you do not stand a chance of being chosen above tonnes of other candidates who applied for the same job. They will take a look at your resume, think that you are incompetent and toss it aside.
This is why it is so important that you have an absolutely perfect resume and that you avoid these critical mistakes that so many people make when they are typing up their resume.
It is needless to say that you should never lie on your resume. You will be digging your own grave if you do get the job and realise that you actually require the skills that you pretended to have. Furthermore, many employers and especially recruiters are now making use of companies that check your credentials and other details of your resume in order to ensure that you are in fact being truthful. If they do discover that you were lying, it can be classified as CV fraud.
However, other than being untruthful regarding the details of your resume, there are other errors that can cost you the job - things that potential employers pick up on immediately and as a result, eliminates you as a potential employee.