Today is a continuation on from the last tutorial. This one will look at a few more tools that are used in modeling your Farmer Joe. The series index is here.
Where we left off:

Here’s where we left off, just the basic shape of the head done. Because it’s going to be a very low-poly model, the head isn’t going to get much more detailed. We’ll add the ears and the hair spike though.
You’ll need to be able to change your selection mode in Blender pretty often, so make sure you’re in Edit Mode, then drag one of your 3d view panels wide enough that you can see these buttons:

These buttons allow you to switch between Vertex, Edge and Face selection. The last button toggles whether you can select vertexes on the back side of the shape (which is something you want in this case).
Build the Ears

Here, I’ve selected the two vertical edges on the side of head and used the Subdivide button to split the center quad into two. Blender doesn’t allow you to create illegal polygons, which is nice though it can sometimes make simple modeling tasks into a puzzle.
Select the two faces that are going to make the ears on either side of the head and hit E or the Extrude button. A dialogue will appear asking whether you want to want to extrude the Region or Individual faces. In most circumstances when the faces you’re extruding are connected, use Region. Since the faces we’re extruding are on opposite sides of the head select Individual Faces. Move your mouse around until you’re comfortable with the size of the new ears and Left Click to finish the extrude.

To pin the ears back and make them more ear and less block, you’ll need to Merge some of the vertexes down. Do so by selecting the two vertexes on the top edge of the ear (use right mouse button to select them individually, hold down shift to add the selection). Then hit Alt-M, which will bring up a few options on how to merge. Make choose either At First or At Last depending on the order in which you selected the vertices. Then repeat for the lower outer edge of the ear, and for the other ear.

The Hair Spike

I’ve selected the two edge segments across the top of the head and Subdivided. This creates a bit of a mess, but we’ll clean it up.

Select the vertex at the center and one of the newly created vertexes and merge them together. Do the same for the second new vertex. Now we’ve some edges in the right places.

Grab the two faces that are now on the top-front of the head and extrude them upwards. Use the Extrude Region option this time, since the faces being extruded are connected.

Finally, select all the vertexes that were created when you extruded and Merge them to the center.

Hooray! The head is pretty much done! It doesn’t look much now, but since we’re making such a low-poly model, more detail can be added with the textures.
The Body

To make the body, just select the four faces on the bottom side of the head and extrude them downwards, then extrude them again to make two steps. Select the newly created vertices and scale them (S Key) to fit your turnaround images.
Limbs!

I would like to extrude both the legs out of the body at the same time, but unfortunately since each leg has two faces, but the two legs need to be separate, neither Extrude Region or Extrude Individual Faces will serve our purposes. So just make one leg at a time! You can see how large the extrude is with the numbers in the bottom of the 3d view, so the legs can be made to be fairly close in size.

Both legs are now done. One extrude to the knee, and another to the bottom of the leg.

The front vertexes at the bottom of the legs are merged into the vertices that make the knees. A block is then extruded in preparation for making the foot.

The new set of vertexes are merged to turn the foot block into a foot wedge and the legs are done!

To make the arms, it’s just more extrudes from the side of the body. This time, Individual Faces can be extruded, so the arms can be created at the same time. To make the hands, just extrude another two levels from the wrists, and merge all the vertices on the ends of the arms to the center:

Modeling is finished! Now hopefully you know the essential tools and where to find them.
You can download the Blender file here.
Next up: UV maps and textures.