You might have heard of 
This post is both an intro for new players and also an in-depth guide. But I don't want to confuse or bore anyone. Therefore, this post is separated into two parts: In part A I will start by explaining the rules in a simple way, so everyone can start playing dcity. I will only cover the most important rules here, so you don't get overwhelmed.
In part B, I will go a lot more into detail. I will discuss some strategies, their (dis)advantages and some behind the scenes rules. This part is addressed to more advanced players. If you are completely new to the game, I advise you to read it later after you tried the core mechanics described in the first part.
Hint: It is very helpful if you have the Hive-Keychain browser extension installed (Chrome/Brave and Firefox), because otherwise you have to sign every transaction manually by entering your Active Key.
Start by opening dcity.io. You will be directed to the info tab, where you can read some basic infos. All these infos (and more) are covered here as well. The info tab is especially useful for checking the stats of any NFT. To start playing, use the login form and enter your Hive username.
Tabs and Login in upper right corner (red).
To have a first look on your city, navigate to the "City" tab. If you are new to the game, it will look like this:
Now, there are a number of stats you have to understand.
In the middle, you can see a big circle. It shows your Population (the number of people that live in your city), your overall Sim-income, and the Popularity of your city. These stats have to be carefully balanced in one or the other way by buying NFTs, in order to maximize your earnings. In simple terms, there are two kinds of NFTs in this game: The ones increasing your base population (population cards), and the ones requiring a certain number of population to increase your income (buildings cards). A building always needs some workers, otherwise it won't produce any income. And your population wants to work, otherwise the unemployment fee will lower your SIM income. The Popularity increases your Population by some factor, don't worry about it now.
There are two ways to get NFTs: You can buy a random one in the "Buy" tab. It costs 4 HIVE or 800 SIM. You might want to convert your HIVE to SIM on hive-engine, because it is usually cheaper. However, I advise you to start by buying some NFTs in the "Market" tab from other players.
For the start, you need some population cards. "Homeless" and "Immigrants" are super cheap, and their disadvantage (negative Popularity) does not have an impact right now. I will explain it in part B. Now its time to buy your fist building. By hovering over the cards name on the market, you can check their stats. At first, you want buildings which require only few workers but increase your income and popularity as much as possible, e.g. a "Gym" or a "Weed Dispensary". In the city tab, try to match your population with the number of workers required for all of your buildings. If your population is too high/low you will see an orange/red icon on the left, displaying how many people are unemployed/needed for your buildings.
The last important point is to check the "Rankings" tab from time to time. Here, every player is ranked by their population. The top 200 players get an additional Steem and Hive reward every single day.
Some additional tips:
Popularity is a huge factor within the game, and it is worth understanding the math behind it. Every population card grants a fixed amount of population, which is also noted on the card. This is the so called base population. For example, an Apartment grants +20 base population (and 5 income). You can check your base population, by hovering over the central circle in the "City" tab.
Your base population is the sum of all the population granted by population cards. Your actual population depends on the popularity of your City, and is usually much higher.
Population = ((Popularity^0.7)/100 + 1) * (base Population)
This is why "Immigrants" and "Homeless" are so cheap. They grant negative Popularity and therefore counter the effect of all the buildings that grant Popularity. This effect can also be used to limit unemployment in your city. Note that the Popularity bonus can't be negative, e.g. your minimum population is always your base population. Popularity also increases the chance to get a random new citizen (Homeless, Immigrant). The maximum is at 500 Popularity with a 30% chance to gain new citizens every 2h.
This leads us to a strategy I want to present: A city with only "Homeless" and "Immigrant" population. If you check the ranking, you will notice some players with negative Popularity and sometimes even income. These players have a high rate of Homeless/Immigrants in their city. They try to get in the top 200 fast and in a cheap way for the daily reward. However, this only works to a certain degree. At some point, the Popularity of a "regular" players city will be so high, that due to the relative bonus it is cheaper for them to increase their population than for a "Homeless-City" owner. Usually,you should look out for the sweet spot between no and only "Homeless"-NFTs. By the way, there is also a project called "homeless-city", supervised by 
Another point to think about is SIM trading. Every random card costs either 4 HIVE or 800 SIM. If you want to invest some HIVE into dcity, you should always check the exchange rate between HIVE and SIM on hive-engine.com. Usually, you can save some money by converting your HIVE to SIM first. On the market, you should always compare SIM and HIVE prices of the respective building, because one or the other might be cheaper. Sometimes, you can even increase your balance just by trading, because on hive-engine, there is often a huge spread between Sell and Buy transactions.
If you already accumulated some cards, you will notice the white fist on orange background on the left side in your "City" tab. This is the crime rate of your city, the probability of being robbed during the night. Depending on whether a "Bank" or "Shopping Mall" was robbed, your daily income will be decreased by 150 SIM or 75 SIM respectively. One strategy would be to avoid/sell these NFTs. As long as you don't have a "Bank" or "Shopping Mall" NFT, you can not be robbed. However, banks generate a high income. Therefore, another strategy could be to have many banks and even more Shopping Malls. This might increase the chance that you only lose 75 SIM instead of 150 SIM when being robbed.
The full equation to the crime rate is a secret, but it is influenced by buildings such as Police Stations, Cinemas and Gyms. Additionally, Homeless and Immigrants might have an effect on the crime rate.
Dcity actually started as a Discord-only game. By now, you can play Dcity without ever having to check Discord once. However, the Discord-Server is still super useful for multiple reasons. The game developer
If you still have any questions, feel free to ask in the comments and I will try to help. Also check out Dcity Discord Channel for news and announcements.
