The general approach is this:
Get the vector of the camera's pointing direction.
For each face get its normal. Note there are two normals for each face, the front and the back.
Using the dot product between the normal and the pointing direction you can figure out if the face is point towards or away from the camera. You typically want to cull faces pointed away from the camera if you are rendering a solid volume. If you are using OpenGL or DirectX, this culling is controlled internally but you can enable/disable it manually.
You'll also want to do some frustum culling http://www.flipcode.com/archives/Frustum_Culling.shtml
This will decide which items are in view and which are out of your viewing area.