Document Everything
Although this may sound silly, the importance of documentation at work cannot be over-emphasized. Whether you are in the role of a subordinate or a boss, document and file every discussion that had lead to conclusive decisions or action. There will come a time when such a simple piece of document could save your day.
What should you be documenting?
Documentation need not be a daunting task. Minimally, document all conclusive decisions or follow-up actions. Document the reasons, rationale and how these conclusions were derived. If there are actions to be followed up, document the Action Officer and put in a deadline (if feasible).
Usually, point form would suffice. A picture may say a thousand words. Sometimes if you can explicitly express it in words, it also shows that you've clearly understood the discussion content and are able to document it.
After you had completed your documentation (either in the form of a simple notes of meeting email, or a formal one), make sure all relevant parties have a copy of this documentation. You should also develop a filing system that works for you so that you would be able to find your document quickly should you need it some day.
When should you not be documenting?
At times, certain discussion content may result in uncertain outcomes that may or may not turn out favourable to you. In such cases, you may want to keep your documentation vague or omit the topic totally. If you're sharp enough, you'll notice that most asian bosses never liked to see their names in any documentation endorsing or suggesting something, probably for fear of future "incrimination" potential when things go wrong. So when you are documenting a course of action or decision that is made by your boss, it would be wise to just document the course of action or decision made by the meeting (not your boss).
Where should I be filing my documentation?
In the modern times, electronic storage is readily available and you should build your filing system on some electronic storage platform (e.g. office network shared folders, your computer's hard drive, external hard drives, etc). Always have a complete backup of your entire filing system in a separate electronic storage media (e.g. your own external hard drive). As with all electronic equipment, you'll never know when they will fail you (quite often at the most critical moment when you needed it most).
How should I be filing my documentation?
I'm using this fantastic COTA-PAO system of filing by Mike Song at GetControl.Net. You can check out their white paper on this unique filing system and attend their courses should you need further help. This system had helped me in my filing journey and I hope it would benefit you as well.