A CV must always be presentable, it is the first impression you are giving to the company about how you present yourself and how seriously you wish them to consider your application. If it has biro marks or tippex on it, the company may think you unprofessional and be unimpressed by the CV before they have even read it.
After detailing you name, address, telephone number and qualifications, add a personal profile highlighting your strengths and objectives.
Then detail your previous jobs under the heading 'Employment History'. Start with the job that is most applicable to the one you are applying for. For example, if you are applying for a sales job and you had worked as a sales person previous to the job you are doing now - detail your sales job first. This will get the readers attention straight away and they will be aware of your sales experience immediately.
Make the CV relevant and to the point. If it is too long winded, the reader will become bored. Use tabs, bullet points etc; to make it presentable and ensure you include all relevant information and experience pertaining to the position you are applying for.
Always check grammar and spelling before sending your CV.