The best summer office job is a job that will give the employee training in her chosen field or experience in a field that she is considering for a career, while also requiring her only to complete the kinds of tasks that can be learned in a relatively short period of time. A summer office job is not the kind of job that should require many weeks of training. It is best to choose a job that will require a week or less of training unless the job is part of a career-building program that requires regular training sessions.
If at all possible, it is best to choose a summer office job that will make sense on a resume. For example, it would make sense for a pre-law student to work in a law office during the summers whereas it might not make as much sense for a student focusing on graphic design to work in a law office. A graphic design student might more logically work in a bookstore that specializes in books on design or art or get a summer office job for a design firm or an advertising agency. The reason for this is that, in the future, it is good to show as much experience in one's field as possible. This sort of resume can lead to an improved chance of landing other, more permanent jobs in the future.
It is absolutely crucial when applying for a summer office job to make sure that the employer understands the duration of employment. If someone takes a job that was listed as full time as a summer office job and then quits in August, not only could it cause problems for her employer, but it could also damage the professional relationships and connections that were established during her period of employment. This could cause real problems for the employee later on when she tries to find people who will give her a good letter of recommendation or job recommendation.
Although it is not always possible to be picky, especially for people who are just getting started in their careers, it is helpful if the summer office job will allow the employee to save a bit of money. This is especially true for students who need to save up money for the coming academic year. At the very least, a summer office job should pay enough to cover the basic necessities, including transportation.