Starting and Expansion Points

Most of the time, you'll start with a castle which is the biggest starting point. Sometimes, you'll start in Camps and that's the smallest starting point. All the castles have 8 building foundations but Rohan have 6. Camps have 6 building expansions. (Plus the defensive foundations). Good have walls and gates. Where you start is not the limit.  

Settlement
Outpost
Camp
Castle

A settlement (200 - 5000 Resources) is where you can gather resources. With Good, there are Farms. Also, Evil have Slaughter Houses and Lumber Mills. Be careful as these are stationary and are a easy target. With Evil, when the building is rank 3, it will fire arrows at the enemy which helps. With Rohan, you can build an Ent Moot. You can spawn Ents and Treebeard. It costs 5000 Resources to build.

An outpost (800 Resources) has 3 building foundations. You can build any of the buildings your faction provides. I tend to build 3 defensive buildings such as a Keep or Sentry Tower to stop enemy forces. Build what you want.

A Camp (2000 Resources) has 6 building foundations and also has defensive foundations.  You could fill it with resource buildings to generate a lot of income. Again, use it to your will. This is your starting point in some places. Good have walls.

A Castle (5000 Resources) is your biggest base. Although you start with a Castle most of the time, you can find them across the map and build another base there. It has building and defensive foundations. Good have the benefit here too with walls.

You may also find some ruined towers along the way. Put an archer or crossbow unit in it and it will fire at enemies. Fire Arrows on the unit will make the tower use fire arrows instead of normal ones. Once the unit is in it, they can't get out so make sure you want them in there. These are handy for picking off little battalions of troops the computer like to use. 

Use these to extend your empire!

Rohan Castle

Mordor Castle

Isengard Outpost

Gondor Camp