Wrong forum, but I suppose a mod will soon move this thread.
To answer your question:
#1 Before you start a new game, go to preferences, and make sure the box that says "always wait at the end of the turn" is checked. Now start a new game.
What this does is, that you always have to manually click the "next turn" button when you are done giving orders, and changing things for your current turn. This makes the game a lot more playable. (I wonder what kind of stuff Firaxis gave to its employees when they decided to not make this standard)
#2 focus on balancing the production of the following 3 things: settlers (to found more cities) Workers (to improve the tiles around the cities) and military units with a high offensive value. (Horseman/knights/cavalry are the best, because they are also fast)
Get as many cities as possible, as fast as possible, but try to keep up with worker production, you'll want about 2 times as many workers as you have cities. Build cities about 2 tiles apart (city center - tile - tile- city center)
The amount of military is something you should develop a feeling for. Try to focus more on military when there is no more free land left, and your borders are against enemy borders.
Expand, expand, expand, and once you can no longer expand peacefully, expand by force, using your military units.
#3 You don't need gold, but you do need commerce, a citizen working a roaded tile will produce commerce. You should turn this commerce into science as much as possible by setting the science slider in the [F1] screen as high as possible. But avoid negative income, reduce the science slider a bit if you get negative income.
The workers you build should road every tile in your empire, to make sure every citizen will be working a roaded tile.
Irrigate plains and mine grassland, improve flat land first, and hills and mountains last
A gold resource on a hill or mountain gives nothing more than a small commerce bonus to the tile. To benefit from it, you just need to have a citizen working on the tile. No road or mine is needed, the road just adds +1 commerce, the mine ads +2 shields.
You should ignore the gold for now, until you better understand how the game works.
To get more gold in your treasury, you just need to lower the science slider in the [F1] screen, commerce will then be turned into gold. But this is only useful if you plan to use the gold for something, like upgrading units. Just having gold in your treasury does nothing.
#4 To wage war effectively, create a stack of units of sufficient size.
Declare war officially before entering enemy land, if you don't you'll have a bad reputation, this will limit your ability to trade in the future.
enter enemy land, keeping your units stacked together, move them to your first target, attack the target with all units in the stack.
Make sure beforehand you will have enough units to most definitely take the target without doubt. If you expect a city to be defended by 2 spearman, you'll need 6 horseman: so you should send a stack of 10 horseman. What horseman are left unused can afterward be combined with fresh units to form a new stack for the next target.
Focus your resources on a set goal, and specialize to maximize effectiveness. Do not try to get every wonder, or build every improvement in every city. Only build what you need where you need it and when you need it. And think about what you really need to achieve your set goal.
