I was in a game where I'm in a -1k gold hole while trying to climb back out. The only ways I can make money were to sell the fish and crops and the bronzeware. So I set agriculture and industry priority to high. But then after a while, my houses start downgrading, so I checked on the status and it said I have 0 musicians working. So out of my 700s workforce, the piorrity mechanic decided empty out my music industry where it only need 8 workers.

So I reloaded he save and tried again, and this time I also set "entertainment" to high to avoid zeroing out my musician. Even though the people kept leaving my city, I was able to see my debt decresed from -1900 to -200. And when I was able to get out of the debt, my houses started to degrade again, and this it said my people were lacking water...are you serious, my well only requires 4 workers max and priority machinac gave me 0. It was frustrating.

Worker shortages can be really debilitating. If the shortage is particularly dire, almost no amount of priority-shifting will keep you afloat. Since the game doesn't provide much leeway in those situations, it might be best to restart and try to improve upon your earlier strategies.

If you had to troubleshoot what went wrong (insufficient food, population too small, etc) what's your diagnosis? Also, if this is a campaign mission, I might be able to help you more.

It's a campaign mission called "walls of zhengzhou". The main problem is that I couldn't make trade partners. The game gave me one at the start but that one only need my cheap fish. There were two cities that want my bronzeware and one that want my silk, but I kept getting rejected when I asked them to trade. I also forgot to build government buildings to collect tax

I remember that one. Which difficulty level are you playing at?

My usual strategy is to slow the game speed down to 10% at the beginning so I can place my common housing block and the first Farmhouse (w/ crops). Once I'm ready, I'll bump the speed back up and watch everything unfold. For missions allowing Silk production, I try to have enough unemployment (approximately 24 workers) to man two Silk Worm Sheds by April of the second year. Pay attention to the growing seasons, because you can take advantage of it:

April: growing
May: growing
June: first Raw Silk harvest
July: growing
August: growing
September: second Raw Silk harvest

Because Raw Silk production stops during the off-season (October through March), you can shut down your Silkworm Sheds during that stretch of time. This bit of micromanagement is beneficial if you need to shift workers elsewhere, but just remember to reactivate your Silkworm Sheds by the following April.

In the case of Zhengzhou, I would get started on Silk before tackling Bronzeware. For one, in this map, you can produce Silk more or less immediately on the mainland (the southern ore deposits require a Ferry). Secondly, fewer workers are needed for Silk:

12 workers per Silkworm Shed
11 workers per Weaver

vs.

19 workers per Bronze Smelter
12 workers per Bronzeware Maker
14 workers per Clay Pit

Keep this math in mind early on, especially since your workforce tends to be limited during the first few years. Of course, this doesn't mean you should put off Bronze production for too long! You may need Bronzeware and Weapons after a while, so don't neglect them.

Regarding other cities, many of them require more "encouragement" before they'll trade with you. At the start of each mission, offer each city a trade agreement. Most of these will get rejected, but you can now see which goods they need. If a city needs Silk, for example, try sending it a medium or large-sized gift of said good. Giving them a desired good will improve your standing with them, so they might be receptive to a new trade agreement. If not, send them more Silk the following year and try again. The same goes for Bronzeware and other tradable commodities.

In the early goings, it's better to earn profits via exports than through taxation. Since taxation requires a lot of labor (62 workers between an Administrative City, a Tax Office, and a Logging Shed), you should hold off until your common block supports a larger workforce. Taxation provides nice supplementary income, but it definitely lags behind the profits you'll gain from luxury exports.

This is probably a lot more information than you asked for, but I hope some of it will be helpful.

Thanks for the info. I always did silk production the last, I'll try putting it on high priority and see how it goes. Now my problem with large population is food supply. My city have 1500+ population, two farms growing two crops, and a hemp farm and 3 fishing dock, and I always ran out of food supply sooner or later. What is the ideal building counts for this population?

Two multi-crop Farmhouses might be enough for the first two years, but you'll likely need at least two more to support your growing population. Perhaps a good rule of thumb is to aim for a third Farmhouse once you're feeding your people Appetizing Food. Keep an eye on the Agriculture tab. It gives you a sense of whether more food production is needed relative to your current population. My personal preference is for there to be a ridiculous amount of surplus food at all times.

Mill usage is also very important. For starters, try to limit yourself to using one Mill. When there are multiple Mills in your city, market buyers will occasionally take long treks to a distant one when the closest one runs out of food. Obviously, cutting down on travel time is vital to keeping houses supplied. Certain later missions might call for using a second Mill, but one is usually enough. You probably know this already, but make sure each type of food has space reserved for it at the Mill. 8 loads per food type generally works. Mill placement also deserves careful attention. It's difficult to describe without screenshots, but avoid placing your Mill at an intersection. In essence, doing so may cause deliverymen and market buyers to walk much further than they have to. Keeping your Mill within a short walking distance to your Market Square is always a good idea.

Speaking of the Market Square, I tend to manually set the Food Shop's priorities. If you only want your buyer collecting a certain food quality, make sure you set both Minimum and Desired to that quality (e.g., Appetizing).