Self-assessments can be used in both professional and personal areas. You can use them to take a solid look at what you do and don't do well. Writing one can sometimes leave a person wondering where to start, but following some simple guidelines will help you make the most out of your assessments.
Be clear and concise on why you are writing an assessment. If this is a career assessment, write down what your goals are and in what time frame you hope to accomplish them.
Be bold and state your strengths in detail. It is important that you and others know what you do well and how you have contributed to the team.
Be honest about areas where you are not very strong. Perhaps you are great with people but lousy on computers; everyone has weaknesses so be bold enough to accept yours.
Once you know and accept your weaknesses, you can create a plan on how to improve upon them (and on your strengths, too). Explain what you can and will do in order to be considered even more valuable than you are.
Write down how you fare in performance against others in similar positions. This isn't a time to put others or yourself down, but to honestly state how you measure up.