Your application documents should comprise your covering letter, CV, certificates and references. Applications should be complete and neatly presented. Correct orthography (spelling and punctuation) is essential.
Your letter should be accurate and concise and meet the criteria of a formal business letter. One page is perfectly sufficient.
Letters of application are usually divided into three paragraphs. The first paragraph should contain an explanation of why you are applying. How did you hear about the vacancy? What made you want to apply? Give reasons why you're interested in working for this company in particular.
In your second paragraph you should briefly introduce yourself. State your qualifications, skills and experience which are required according to the job advertisement and fit the job description. Explain what you have to offer. Refer to the specific requirements listed in the advertisement.
In the last paragraph, declare your interest in attending an interview. Offer to send additional references and information on request.
Your CV should summarise your training and career so far and provide an insight into your abilities and aptitudes. It should be up to date, clearly laid out, and not contain any spelling or grammatical errors. It should include the following information: your personal data, your education and vocational training, relevant work experience (previous employment and internships), special skills and experience, your language skills, computer skills and your interests.
Your certificates show the educational and professional qualifications you have and thus augment your CV. Your certificates should be sorted chronologically starting with the most recent one.