Welcome, esteemed peers. In this guide we'll cover the basic tutorial in an easy to reference fashion, and I'll offer some useful advice on how to manage things around the kingdom for your best chance at success.

Let's start with setting some expectations.

Your nobles can and will kill you. Your goal is to appease them where you can in hopes you can accomplish your ambitions before they manage to pull off their scheme. This means not acting high and mighty. Be humble, these are your subordinates but they also control the keys to your power. The fastest way to die is to unify the nobles against you.

All noble houses want you to lose power, but crucially they want to be the ones to do it, they want to win. You should play factions against each other, encourage infighting so that one group might sabotage the next's chances if they stand to pull ahead in scheme progress. This will require careful management of your relations with the houses, but done right can take some pressure off.

Also, don't be afraid to ham it up a little, make a show of being nice to certain houses, marrying their sons or daughters, and offering high praise to whoever you choose to be your bodyguards.
Side note: choose carefully, these warriors make assassination attempts against you by a rebel house of the same origin have a much higher chance of success, I speak as a successful employer of assassins and source of house guards.

This game really shines when people get into the spirit of things and embrace a little bit of an RP mindset. You should lead by example.

Here's a scenario I had happen while I was king:
Northerners had an avalanche hit them and I tried to set up a memorial. It went poorly as an archbishop decided to smack talk their ancient beliefs and blame them for it. Naturally, this had the Northern Chiefs up in arms, but I offered a royal apology and explained that I sympathized and wanted to try and get the archbishop to apologize.
Even if the vote doesn't go the way I want, I still had some sympathy from the chiefs as I had tried to champion their interests. It's not enough to keep me safe from their scheme in the long run, but it stops them from adopting the "Screw this king, lets burn it all down! I don't care who's holding the torch." mindset and can cause some nobles to become loyalists to a degree if the player is kind spirited enough. Empathy can go a long way.

Noble houses start with certain stats and have specific agendas they like. You can use this to your advantage.

The Northern Chiefs reject the Ninth god and want their old religion to make a comeback as a part of their plans to overthrow you. This means that they start with a faith score of zero, and tend to want others to lose faith too.

The Southern Grandees on the other hand, are paragons of virtue (in public) who strongly believe in the Ninth god and use the modern church in a good number of their schemes. They start with a high faith score and usually want to keep it that way.

By choosing these two houses, you can slightly tilt the scales and potentially have them get in each other's way. Failing that, you can at least try to use this characterization to stir up animosity between the two houses, potentially preventing any alliances.

Over time, you'll gain more experience with how the houses tend to operate and be able to set them up against each other more easily. Pay close attention to your nobles and ensure that some traditions and cultural differences are thrown into sharp relief if you can.

If the past two steps don't give you the leg up you need, you have one last resort.

You can't use soft power and manipulation all the time, but you aren't entirely out of luck yet.
Voting laws are a tool that all monarchs can access a short time after being crowned, though the starting two laws you get are night and day in terms of usefulness. Laws have a cooldown so you need to manage them carefully and ensure you know what you can use when. I'll update this section with more laws as I encounter and assess them.

To start you have two laws:
Monarch's Choice
F Tier - essentially useless as it does nothing other than show what you want to pass. Has extremely niche use as reverse psychology tool if everyone wants to do the opposite of what you want. Fingers crossed in the future they'll buff it to at least count as a vote toward the choice.

Veto:
S Tier - unrivaled as the best law in the game by far. It entirely removes an option from being voted on. It's essentially a panic button for if a really bad option comes up and you think it could get passed, but it has a cooldown so be careful when you use it.

Eventually you'll have a third law of your choice (the max number of laws), then get the option to replace laws you already have available. Obviously that's going to be the Monarch's choice at first, but after that it allows you to be a bit more reactive.

Reverse Voting
A Tier - Now this law is interesting as it massively increases the coordination needed by the nobles to force a specific issue. If there's a strong movement in your chat to pick a choice that's bad for you sometimes you can sneakily enable this law and if some of them don't notice you'll break the movement entirely. Used sparingly, it can catch nobles by surprise and really help

Monarch's Iron Choice/Call For Unity
A Tier - Having your authority or stability hit zero means game over, these laws let you get a +1 to one of the two if the law passes, which can keep you in the game when things look rough. It can add a silver lining to having something awful pass, so don't be afraid to use it if you can see the writing on the wall.

Monarch's Golden Favor
B Tier - This law gives 500 gold to any noble that votes for the selected option. Depending on how much your nobles get greedy, this could actually be pretty good.
The downside of nobles having more money doesn't really matter because two buildings will get built every build phase no matter what, the only thing that could change is a faction being able to outbid the others if they always vote your way but everyone else doesn't.
Ideally you'll make far more headway with the votes you pass with this then they will in a single round of bidding. Has limited usefulness if your nobles decide they don't care about money/winning bidding wars.

Royal Wager (Not sure if that's what it was called)
B Tier - This law allows you to gamble treasury money on a law passing. This is very similar to Iron Choice and Call for Unity above but are strictly worse as failure has a cost that actively hurts you in a stat that can end the game if you run out. The treasury isn't easy to replenish, so consider that very carefully before committing to this law.

Anonymous Voting
C Tier - Good if you're playing in room mode, largely useless in twitch mode as anyone can just look at chat and see who voted for what.

Stop the Count
D Tier - This automatically ends the voting after 15 seconds. With twitch latency, all it will accomplish is annoying literally everyone as no one gets a chance to vote before its over. In room mode, maaaaybe there's a point to it, but I doubt it. Definitely not worth keeping as a law unless the other options are somehow worse. Gets D tier because at least anonymous voting doesn't tick people off.

I'll leave you with some final advice for when nobles realize their house can't win and begin considering alliances:

The nature of this game is that dynasties aren't just for the monarch: Nobles can build up for next game too. That is to say, the money they collect, the improvements they make to their lands stats, and the storylines they start can all help them next game, but only if your dynasty is still in power. If another noble house overthrows you the game is over and you have to start a new dynasty and everything resets to default.

Remind them that being loyalists is an option, and is the only one that guarantees them another shot at the crown. Helping another house win is giving up all the work they put into gaining money and improving their lands, so they might as well try to help you win so they can crush your successor.

With these lessons, you should be ready to try and take on the nobles and secure your power!
As always, your experience may vary, these are guidelines, and I welcome any constructive discussion in the comments about ideas posed above.

If this guide was helpful or just an interesting read, please give it a little love and rate it up.
Long live you, my fellow sovereigns!