The 3D window is where you will spend most of your time in Blender. In this window, you can rearrange the objects in your scene, edit their individual vertices (vertices are the points that make up an object), define animation, add lights and cameras.
The first thing to know about the 3D view is how you can navigate through it. I am not talking about moving objects, but about moving your viewpoint - how can you examine objects? How does an object look from another side? Do the different parts have the correct color? Did I add a little detail correctly?
Blender uses a very simple yet intuitive method for changing the view in 3D. To get started, press and hold the middle mouse button and drag your mouse around. Do you see what happens? Without any modifiers, middle mouse rotates your 3D view.
Now try the same but hold down the SHIFT key before you click the mouse button. The view is now translated instead of rotated.
Finally, the CTRL key allows you to zoom in and out. To toggle between perspective and orthogonal view, press numpad 5.
In the 3D window, you can display your scene in a number of modes. Especially if you don't have 3D hardware this can make a huge performance difference. To toggle between wireframe and solid view, press Z. Solid view can display a scene with some shading even though you have not yet defined a lamp.
Switch to (real) shaded view with SHIFT+Z. If you have not defined a lamp yet, the scene will be completely black.
Aside from navigating around 3D space to look at your objects, you can also use a few hotkeys to quickly switch to standard views. Use numpad 7, 1, 3 and 0 to switch to top view, front view, side view or camera view.
Sometimes you may get lost inside 3D space a bit. To restore the view, either click on the home icon at the bottom of the 3D window, or press HOME. Blender will resize the view to include every object in your scene.
Tip: The Blender User Interface components work in the same way as the 3D Window - you can translate and scale any component. The key works, too.
If you want to get a specific object into view and not the entire scene, first select the object by right clicking on it (the object will turn pink to indicate it is selected). Next, press numpad dot.
A similar function like the previous one, you can also zoom in to the selected object and hide all other objects at the same time by pressing numpad /. To unhide your objects, press / again.