Pay attention to the Civilization Chart on page 17 of your manual. This table shows all the special qualities and abilities each Civilization has available.
Build a Courthouse as soon as you are able. This structure reduces corruption in whichever city it is built in.
Build Ports when possible. A port gives you extra resources, as well as an extra tile for a unit to stand on.
Early on in the game, be careful to keep a balance of defense, research, growth, exploration, and culture.
There are several different types of terrain. These are listed on page 61 of your manual.
Remember, some units cannot travel over certain terrain types, unless there is a road built to ease the way.