All good papers start with a strong outline. To begin your outline, make a list of the areas of your life you want to assess. Next, gather evidence of your accomplishments and setbacks, and decide what criteria you want to use for your assessment. Go back through that list and think of what actions you've taken towards your goals. Finally, break the outline into sections; each section should focus on a goal and the progress you've made towards reaching it.
In the event that you are writing a self-assessment paper for the purposes of a job, start your paper by gathering evidence of your accomplishments and setbacks during your career. This may be in the form of promotions, pay-raises and letters of recommendation on the one hand, or demotions, suspensions and letters of reprimand on the other. When writing about these instances, be honest and critical where appropriate, but also showcase your strengths.
Choose a logical arrangement for your paper before starting to write it. For example, highlight your lesser goals first and build towards your larger, more important ones. Alternatively, begin with the biggest goal first to emphasize its importance to you. Strive to include personal insight into how your life experiences have helped you grow and the direction you wish to take in the future.