Many people are inclined to recite a list of traits such as "dependable" or "creative", but it's especially effective to discuss experience or skills that are directly related to the internship/training program to which you're applying. For example, if you're applying to intern/train in Sales but have no previous sales experience; highlighting your presentation skills might really impress an employer. Or you may want to provide an example of how you were able to persuade someone to do something since that is the foundation of the sales industry. Again, provide actual examples rather than a list of attributes.