The year gets busy and it can be hard to remember all you've accomplished when doing a review. Develop a method for tracking your progress. Create folders on your desktop and keep emails from co-workers on key projects, successes and business gains. Keep a spreadsheet on completed projects and note if they were on time, under budget or measured by another key business metric.
Try to record key milestones once a month so you have an easy reference list with key metrics at the ready — especially if your company includes a self-review in the process.