You have learned to create brushes of all shapes and sizes with the box tool and object properties window, but you have also learned how to make quick copies of existing brushes with the cloning technique. When an object is selected in a 2D viewport, you can scale an object when there are eight white handles surrounding an object, rotate when there are four white circle handles surrounding an object, and skew when four white boxes surround an object. Flipping objects is a useful technique that can save time when making symmetrical creations; Ctrl + L flips horizontally while Ctrl + I flips vertically. The Vertex Tool is useful for making irregular brush shapes, but it's also useful to create new edges on a brush using the Ctrl + F command. The Clipping Tool is useful to cut parts of brushes or split brushes along a line. Remember that when a section of a brush is highlighted in white, it will be kept after it is clipped. If the section is red, it will be deleted. The carve technique is useful to put square holes in square objects. You can carve anything with anything but you're going to get some ugly brushwork as a result. 2D and 3D SkyBoxes are easy to create, and enhance the atmosphere and immersion in any map.

I bet you're getting tired of looking at this default brick texture. Let's learn how to use the texturing tool to its full potential.