I have been working on writing a case for my promotion and one of the biggest challenge that I face is bragging about my own achievements. I took the advice from Rahul's other post and started keeping a daily todo/brag doc. Its a bullet point list of things that I do on the daily basis and has been helpful.
But when it comes to creating a full blown promo case, I feel there is a need to focus on the impact and actions in a more verbose way and I really struggling with that. Maybe I need to learn more documenting skills.
Any suggestions or even resources I can refer to improve my writing skills would be appreciated.
I'm glad the bag document is helpful! (Make Your Promotion Case Easy - Keep A Brag Journal). In terms of writing skill, almost all the best practices about writing a good resume should carry over (e.g. "show, don't tell"), so watch that masterclass if you haven't already: [Masterclass] How To Write A Stellar Tech Resume That Gets You More Job Opportunities. I'd also get your promotion doc reviewed by your manager (at least) so you can improve it based on their feedback.
Also, keep in mind your self-review is just one component of your promotion case. Equally important are your peer reviews -- feedback from your colleagues about your strong performance and why you're deserving of promotion. This is perhaps the highest leverage thing you can do to better document your promotion case.
At the beginning of the performance cycle, identify who your likely peer reviewers will be.
Before writing up the promotion case, hunt down the OKRs for 1-2 levels above yours. That will establish a baseline of what your org's overall goals are and how progress is measured.
Next, map your contributions to that baseline. Expand the definition of "contribution" to include what you had an influence on vs. only your individual output. If you can get feedback from stakeholders on initiatives and decisions you influenced, that would make your case stronger.
You'll likely have a laundry list of things at this point. Aggressively synthesize this list to the most impactful things. Depth backed with supporting evidence is going to be stronger than breadth. You're trying to reverse engineer the process that gets you a strong rating, which is largely influenced by a 2-minute pitch in most places, so you want to use this window wisely.
Unfortunately, most managers are not good at delivering a 2-minute pitch (or don't care as much as you do to refine it). You want to make it as easy for them as possible. Ideally, work with them in a 1-1 on how to translate the BRAG doc into a 2-minute pitch to reduce the margin of error.
I find it helpful when engineers keep track of their goals and aligning them to company/engineering core values. Some companies have leadership principles and aligning them into those buckets based on the goals you accomplished throughout the year. Here's some examples I ask my direct reports to keep track of.