Recently I had a friend talk to me about completing an annual review for their job. The end result was this person wasn't seen as accomplishing a lot, and didn't get the raise they expected. However, their view was different. This individual felt they'd worked hard all year and had accomplished a lot.
When I asked the person what they'd done, I received some general thoughts about working on this project or that. The individual was insistent that they had spent a lot of time at work after hours solving difficult problems. When I pressed for which problems, or which projects, there was a lack of detail provided.
No one is going to track the work you do. Even on big, highly visible projects, it's hard for a manager or others to remember your individual contributions. Even if you complete some project by yourself, your manager will be worried about their own accomplishments, and those of their other direct reports.
You need to track your accomplishments throughout the year.
Use a blog, a Word document (back it up), Evernote, OneNote, or something else. Make notes throughout the year and have them ready when you get prepared for your review. Include specifics. Note the tasks that you actually completed and have a specific way to describe them quickly.
Summarizing your work for the year is almost like a book report. You want to take the story of your work year and provide a report that both condenses the year into a few sentences, but includes specific details that highlight your contributions.
Very few people will do this, or be prepared in advance, so a little effort can go a long way towards advancing your career inside of an organization.