personally I would strongly suggest you to learn to box modelign in Maya first just to understand how things works fundamentally… it will serve you better in a long run if you really want to make a career out of it.
if you really want to learn Zbrush, you should take a step back and work on each part of the body first. It is extrmely easy to go overboard and add alot of wrinkles and detail on zbrush before you nail down the basic porportion. This is what is happening to your model.
Before you can add cloths on your model, you have to understand how does a basic human body works first so you know how the cloths will fit on the body. Do you understand the overall shape of a human arm? Do you know how does a human arm connect to his shoulder? Do you understnad how to give your character a good porportion before you work on the detail? What is the relationship of a human head to the body? how does the mucles and line flows work on a human face? How do you model the human eyes? lips? nose? How does a human hand look like?
These are all the things you have to understand first before you move on to a more complex things such as giving him the details on his cloths and give him accessories…
If you are just trying to have fun with experiencing the program, by all mean, go ahead and have fun
nothing is better than creating your own model that you dream about. BUT if you are going to be serious on becoming a good modeler, a good understand on the fundamental rules/techni on modeling is strongly recommend before you develop a bad habit on your model style.
Go to google, and look at as much cg models as you can. Dont start with something complex like those Hulk or aliens model you see in cgtalk. Start with something easy first, such as your favor cartoon character. Learn to nail down your model’s porportion before you go for the detail. Look at as much tutorials as you can online and try to mimic how thsoe artist model…
make sure when you model your character, you will have a reference picture of what you are modeling. You aren’t experience enough to do it out of your head yet… In fact, even the most experience modelers out there will require a hell lot of reference picture for their models, and you should be no exception.
good luck in the future man. It’s a good start, but I am always a fundamental kinda of guy when it comes to 3d. If you don’t have a good foundation in 3d, your work will not look good, be that modeling, animation, or anything else.