We have to be sure that you will be capable of undertaking a doctorate level of study. The style of your application form also reflects how far your work is grounded in psychological theory. Research work in a clinical relevant area is preferred. Some clinical experience is essential. A reference from a clinical psychologist with whom you work is useful, particularly if they have worked with applicants to clinical psychology courses before and have written references in the past.
Quality is more important than length of experience.
Your clinical ability will be judged by your experience, the way you present this on the form, and your clinical reference. This will be judged using your application form and your references. A little information about your interests and activities outside work is helpful in presenting a well rounded picture of you as a person. Your commitment and motivation will be judged by your career path to date, the way you express this in the form, and your references. References These are important.