To write a self-assessment, include details about accomplishments with tasks on the job or in the classroom, highlight strengths and weaknesses recognized during a specific time period and provide examples of how performance can be improved, according to Chad Brooks for BusinessNewsDaily. The assessment should be honest and concise.

When writing a self-assessment, support all claims with evidence, reasoning and relevant experiences in the classroom or on the job, explains the Foundation for Critical Thinking. For example, in the workplace, detail accomplishments such as deadlines met, sales goals achieved and successful team projects. In the classroom, detail concepts learned and applied on specific assignments that have prompted critical thinking and analysis. Refer to workplace performance reviews, instructor and peer feedback on assignments and guidelines provided for writing a self-assessment provided by the company or instructor.

Acknowledge mistakes professionally when writing a self-assessment. When highlighting weaknesses and unsuccessful attempts at completing a project or assignment, write about how preparation or different approaches could have improved performance. Assess what was learned by the mistake and provide examples of a renewed approach to improve performance in the future, notes Amy Gallo for Harvard Business Review. In addition, keep the focus on personal performance versus company or school policies. A self-assessment should be diplomatic and show writers are willing to take a critical and honest look at themselves.