There is a lot to do and I recommend you read already existing article/documentation on Optimism and DAO in general.
What to expect from season 4 and changed expected to be implemented. Get yourself familiarized and, possibility, provide feedback. Topics tagged season-4 , I wrote a noob version here
code of conduct - Delegate Code of Conduct
single source of truth for DAO proposal process is mentioned in Optimism Operating Manual Operating Manual v0.3.5: The Token House and Citizens’ House ,
GitHub - ethereum-optimism/OPerating-manual: OPerating Manual of the Optimism Collective. https://optimism.io/vision
Major protocol upgrade till date - [FINAL] Upgrade Proposal: Bedrock - v2
Read on Citizen house and RPGF - Introducing the Citizens’ House: 10m OP to Public Goods — The Optimism Collective
Optimism Super chain with Base Optimism Goes m̶u̶l̶t̶i̶ Superchain — The Optimism Collective
Follow Optimism Gov twitter handle and join Discord and follow the conversation there as well Discord
DAO is working on iteration which bring new changes each season depending on feedback so I encourage you to read final roundup announcement of each season. Season 2 was particularly important as it was more chaotic, full of unnecessary noise and confusion for everyone involved and could be seen as one step forward, two steps back but changes were implemented in season 3 to overcome those challenges.
Those links will give you a head start but its only 20% of full picture, so read, understand and contribute where you can. No one has knowledge of everything, which is jut fine.