Modeling: A Million to One - Blender Foundations: The Essential Guide to Learning Blender 2.6 - page 67

Things get faster and easier from here.
We'd like to make a whole additional
column of faces extending to the right of
the ones we just created, but it would be
nice to avoid adding vertices and creating
faces by hand this time. The simplest way
to do this is with the Extrude tool.

Extrude can be found in the Modeling
section of the tool shelf, but since it is
perhaps the most commonly used model-
ing tool, it has its own top-level shortcut:
the E key. Extrude takes whatever is a
part of your current selection (vertices,
edges, and faces), creates new attached
copies of those elements, and lets you
move them around. It's easier to see it
in motion than to read about it.

Make sure you're in Vertex select mode
and select the rightmost column of ver-
tices. Press the E key and see what
happens. Those vertices and edges are
duplicated, and the duplicates remain
connected to the originals, forming 11
new edges, 6 new vertices, and 5 new
faces. The new elements are automati-
cally put into the equivalent of the G-key
translation mode so that you can position
them as you like. Pull the new geometry
to the right a bit, creating something like
Figure 4.11 . Using RMB selection and
the G key, try to make the resulting petal
roughly symmetrical.

Figure 4.10 The inal result of polygon-by-polygon modeling.

Much simpler, no? Usually, you will be
able to get away with creating just the
beginning of your model “by hand.”
From there, you can usually extrude your way into anything that you need. Of course, there will be times
when you need to bridge a gap in the mesh, connecting two different sections or some other specialty.
On those occasions, you will need to know how to add individual vertices, connect them with edges, and
use them to create faces from scratch.