To become a summer trainee, it's important to first research all of your options for internship positions. Make sure you choose a trainee opportunity in which you'd be an ideal fit. Also make sure of your availability for the times and dates of the trainee job placement before applying. Having the proper address as well as a contact name, along with your application and persuasive cover letter can start the path to help you become a summer trainee.
Begin your cover letter by mentioning that you are the ideal person to become a summer trainee for that particular company and list several reasons why. For example, you could refer to past work or educational accomplishments and/or your values, skills and future career goals. It's best to stick to one reason per paragraph and end the letter by asking for an interview at the reader's earliest convenience.
Being persuasive and enthusiastic, but also professionally polite, can go a long way in helping you stand out from the competition to become a summer trainee. Also, proofread your letter and resume many times as well as have other people check for spelling, grammar or punctuation errors. Ensure that the address and contact name you have are current. Try to send your application before the deadline.
Especially if your goal in a summer trainee position is to receive full-time employment at the end of the opportunity, do your research on the company to understand how it operates and is organized. During the interview process to become a summer trainee, if the subject of your future career plans comes up, be prepared to mention that you hope to work for the company and why. If you're sincere in your answer and can convince the interviewer you're a good fit with the company, you're likely to have a good chance of getting the trainee opportunity.
Also be sure that you understand ahead of time the duties the summer job will require, as this will make it much easier for you to be convincing in your assertion that the tasks are ideal for you. Remember though that learning is expected of a summer trainee, so overstating your knowledge or appearing to be overconfident may backfire. Instead, if neither your education nor experience fits with expected tasks, make it clear how you're not only willing but capable of learning new skills or procedures during training.