you can try blender as a 3d application because its free. Z brush is better but expensive and usually it is used in organic modeling.

Regards to designing, you can first take a look on some other advanced artist work, not to copy them but to train your brain and eye to recognize what is beautiful.

As all artists have been, they take inspiration and borrow design from their surroundings, nature itself. Ex. the volkswagen, there is a reason it is called "the beetle" or the elf warriors' armor in Lord of the rings which look like leaves. Mixing concepts is also a good idea too.

Its easy to create concepts unless you have a noisy left hemisphere brain that always wants to tell you what to do which you can always shut up by drawing and let the quiet right hemisphere work. Once you create a habit and practice all the time by having a neat little sketchbook with you wherever you go to jot down and sketch ideas, you will be a design machine.

A simple practice:

Find a jacket in your wardrobe. Then think, what can I do to make this look COOL? Think of a setting like, what if this is a jacket used for outerspace? Take a quick research and draw some little inspiration from nature or anywhere around you. Create your first design, it may look weird and not that cool but don't throw it away for you might be able to use it later.

You may overdo it with detail and sometimes simplicity and making drawing a habit is the key.

Since you are a beginner in poser there is a site called www.poserpro.net which have a general info in making clothing, dynamics etc and the rest you can find on the poser forum tutorial links so good luck and stay healthy.

Passion is anger and love combined. So if it looks angry, give it some love!