There are some great ( and free ) templates for games that you can use also, so that as a 3D artist you can start placing your models within an environment, press P ( the Play key for starting Blenders built-in Games Engine ), and seeing your content live.
Here's a cool 3rd person platformer one, with support for a LOT of features such as moving platforms, jumping etc...
Third person adventure - Template v.01 - Blender Artists Forums
Someone has started a FPS here...
Simpler FPS Template - Blender Artists Forums
If you're new to Blender, I'd recommend downloading the 3rd person .blend file ( after downloading the latest version of Blender from
blender.org - Home of course ), opening it up, and pressing P.
Mal