As you know, with gold everything is easier and faster. Having gold allows us to upgrade our city without taking any breaks due to not having resources or because of having to wait for workers from City Hall. Having gold allows us to buy everything that we need from other players. 1 gold is equal to approximately 33.333 resources, which is pretty much and will let you build at least 100 buildings or we can buy around 70 workers. So it's logical that we don't build factories at the start but build houses to get more workers and increase the level of happiness. Having more houses allows us to have more workers and it gives us an opportunity to increase the speed of building our city.
We should also build some warehouses to storage resources that we bought or we will have to buy them every time we build something. After that, we are going to start building some factories except for gold mine. Lots of people started building mines and extracting gold too early, which is wrong because mining gold is too expensive and we can easily stop improving our city and, with that, improving our game. We build as many factories as we can: having more factories will give us a chance to mine gold faster and improve our city while, at the same time, getting money.
In general everything is very simple - from the scratch you should upgrade your houses to the maximum lvl and have around 10 of them. Having this amount of houses will give you a lot of workers and for some time you will be able to build everything you want to build during the same time. This basically means you would have to log in the game once every 6h (depending on the size of your city, number of workers, number of buildings under construction and so on). In the end, I want to say that, if you want to buy some gold, 1 of it isn't enough in my opinion. You should get yourself around 10 gold to increase your city on a good level and manage to get your money back. I remember that after 16 days of playing I could have had 100$/month if I would stop building my city and only sell things like resources/workers. But I decided to invest these things into the game and have bigger money out of it later.