By using the contours at the top of the rear leg you can shift / move them two polys up, then delete the middle set (so as to seperate the element again. From here you can shift move them and continue creting the back from the base of what you have already created. Here is the back area filled out.

The arm socket area is generally quite tricky to get right in practice. When you have to take into consideration the animatable properties of joints, you have to note how the vertices will be efffected. Even the poly layout has to be considered as you do not want to have polys jutting out and looking bad. As each square is made up of two triangles...you have to consider how those triangles will deform once it is to move. It is difficult to see the effect until you actaully get to that part, but over time you can see where problems may arise and sort them out.

For this exercise I took no regard in how triangles are sorted...so if the problem arises, we can work through it.

Because it is a coat though, and not something closer to muscle tone, we can take it a little easier in regards to detail.

As you can see I have started the arm in sections. I know what the arm is to be (basically a cylinder) and I have the front of the shoulder area as a basis for the back (although it blends more into a flat area rather than a chest) and this is what I have made from those parts of information.

From here we can join the two in order to make sure it flexes well once we have added the skeleton.

A good thing to consider is the more an area needs to move, the more polys it will need. In this case the top of the shoulder and underneath the shoulder, to less an extent. As the top of the shoulder needs to flex over the when the arm is at it's side, you will need to blend the vertex assignments to make the transition work well.

What I have done here is a rough version, once again it will need to be refined once I move through the second, more refined version after the basics are made. (Once again this is just how I work, it's not gospel or anything)

The arm is 'basically' a cylinder but with some extra polys around the elbow area for the bending. As the back of the arm will need to bend more then the front, there is more polys to go round.This will be better seen in action after we have rigged the character.

Here I have started the wrist and hand by pulling back the edge vertices of the coat arms, scaling them along one axis at a time to flatten it out (look at your own forearms to see what I mean) and then pulled those edges forward once more to make the wrist.

Shift / Moving the edges once more I start the hand. Tweaking the vertices a little I start to get the curves of the palm.

Here is the hand. As I am making seperate fingers for detailed animations I have to keep them pretty rudimentary. The area around the base of the thumb needs special attention as it is an area that moves a lot once you start animating. So far I've never really got it right myself I have to admit, so your on your own there :)

Here is where I focused on the neck, tweaking vertices as I go along if I see anything out of place. At this point I joined up the vertices in order to get them to line up exact, I will be detaching the head once more (but only as part of the element, rather than a complete new object) in order to continue the coats collar.

Once I select all the head and neck (the line where I want the collar to start) I detach it (selecting detach to element in the option window when you do) and move the head down or up so you can easily select the edges of the coat where you want the collar to go. Shift / Move the edges up, move the vertices around if need be (in my case the one at the front to make it not so square) and then apply a different smoothing group to it.

Alright! So a few shortcuts were taken on my part, but I still have only used the information and methods I have given in the tutorial so far. It all comes down to knowing what you want, and using the knowledge you have of the subject and medium in order to make what you need. The arm and hand, for example, was all done without reference.

All I can say is to practice, and to study. Look at the world around you, and for characters such as this there is no better reference than yourself (I mean, it IS a self portrait...of sorts). There is also a WEALTH of reference out there in books and the web. Scout it out, you'd be surprised what you can find :)