This is the easiest bit of the game to make a reputation for yourself in some ways. While it is absolutely true that a lot of the politics happens in advance, this is the one place in the game where sometimes you are going to change the result by swaying a lot of opinions very quickly with your public speaking. If you have a point to make - don’t be afraid to make it! Even if you haven’t joined an order, most Grand Masters will let someone speak if they have a point to make - just ask. If you are a confident public speaker - great, here’s a chance to let your skills shine - but make sure to respect the time of your listeners. If you are not a confident public speaker, or are not playing one - sometimes that can actually have a bigger impact as the nervous Mage with the shaking voice manages to make the point that the debate really needed to hear, and everyone understands how high stakes it is.
It will probably really help to go over the agenda - or at least some of it - with someone more experienced, in advance. If you have a sense of what the agenda items are, you can form opinions and do a bit of research in advance. “I hear someone’s raised a declaration of interdiction against the Imperial Crown! What’s that all about?” or similar about whatever today’s most controversial motion is, is a good conversation starter elsewhere on the field.
My absolute love of conclave comes from the way that the politics and the interpersonal relationships all play out publicly. Watch for people’a reactions! This is where the social PvP happens hard and fast in real time. If you attend multiple sessions you will get to know all these tidbits of characterisation, drama and gossip about the regular attendees - who hates whom, who is secretly in love, who’s buttons it’s really easy to hit on a particular topic… For me, that’s where the real jam and interest comes from. It takes a bit of commitment to get there - to stick around long enough and pay enough attention to really be able to watch those currents. But you don’t have to play that way, if it doesn’t sound like your fun! It’s equally valid to only show up if the debate is relevant to your other game; and your voice can be just as loud if you are saying the right thing at the right moment without that kind of commitment. The fact that you can find reward from both high investment and low investment play is one of the things that’s really damn cool about Conclave.
Final thought - yes, I can’t count to three - if it’s gotten brutal, which it can do sometimes, take some time to check in OC with people. It really helps to make it clear that the conflict is in character - sometimes it can hit close to the bone because people will be talking about what might feel like you real public speaking or confidence or competence skills. It’s all bark and no bite, and pretty much anyone will be cheerful to help you out OC if you need it!