If it's review time and you think about what you should put in there you have already lost.
This should be an ongoing process where you continuously look at the work you are doing, the work you want to be doing and reflect about what works, what doesn't work and the progress you are making.
Each week do a small dump of the above in a text file. Every other month review, reword, compress what you already have.
When review time comes you just dump the text into the review form. No need for stress, no need for thinking about it in the context of a review. This will also give you the time to identify and improve as needed. Improvements will not be a forcing function of the review - you are already working on it - and your manager will appreciate it you can clearly articulate this.
Another thing that helps is once you get good about reflecting about what your challenges and strengths: get a mentor. Be open, learn and improve on the know-how of someone who has "seen it before" and can help you accelerate your growth.
Last thing: the review is just a review. It's not necessarily a true reflection of reality. People can and will game the review system. Your focus should be on improving yourself and bringing value to your employer. Once you learn to continuously do this, you will leave the clowns that game the system way behind in your rear-view mirror.