Congratulations! Your CV, cover letter or application means that you've convinced the employers that you meet the person specification for the job. Now the hard work begins!
An interview is a chance for the employers to meet with you and find out more about you as a person, and whether you'll fit in with the organisation and their way of working.
Many graduate jobs interview candidates at group assessment centres. These typically include a group activity, to assess how you work in a team, an individual activity, such as a presentation on a problem they have given you, to assess your problem solving skills and an individual interview. GSK have prepared a very good guide to all elements of an assessment centre.
Never underestimate the amount a preparation that you have to do for an interview. You'll need to have done your research on the organisation, printed out the original CV / cover letter / application that you sent in, sat down with job description and person specification and predicted the questions that you'll be asked, prepared a presentation (if you have been asked for one), gathered any other supporting information, and thought about the questions you are going to ask them. Make sure you set aside at least one whole day to complete this preparation.
In the interview, your potential employers will be trying to find out how well you could do the job. In almost all cases this means going through the job description and person specification, asking you questions about each one. This means that you if you spend some time looking carefully at the job description and person specification, you will be able to predict almost all of the questions that you'll be asked.
Strangely enough, hardly any candidates bother to do this. If you do, you will instantly stand out from all of the others.
Yes, an interview is not a memory test. Here are a few things that you might want to take along with you:
Always ask questions at the end of the interview. If you don't, it will look like you're not interested in the job and in the organisation. Asking the right questions at the end of the interview will impress the interviewers, and will also help you to find out much more about the job and whether you want to work for the organisation. Remember, it's fine to take in some questions to jog your memory.