You might also get started by modifying existing clothing models, either the built-ins or free stuff. One way is to make transparency maps in an image program like PhotoShop - the cat suit is a favorite because it covers so much of the body. If you want to model clothes, load some in Poser without a figure and look at them with the various view modes (wireframe, shades with lines, etc.) to get an idea of how they are made, and the various approaches people use. An easy way to get started with modeling is to modify clothes models inside Poser with its magnets and deformers, which are well worth learning how to use. There are some good tutorials around. Have fun.