When the head was finished, it was time to finish of the model by creating the body, making sure that I paid particular attention to getting the proportion of character right. If in such cases when you come to create your chosen pose and you are finding it difficult finding reference information regarding this, what I tend to do is use one biped (from character studio or CAT), and shape over it, using it as a wire structure.

Following a tip of 'to do a particular part of the body you have to draw the general form and then later refine in with all the smaller details', which I was taught by a my teacher at College (Teacher Cláudia Amandi), I started to shape the T-shirt, modelling the basic form, and later adding in all the detail and adjustments.

So here is the finished T-shirt, with all the details that I have added. As this is a cartoon character, you don't necessarily have to make it look very realistic and react as it would do in real life. What is more important is getting the final look right for your character.