Hi DeputyDubbaU,
The best way to go about doing this, is to extract the ped model's textures for the actual uniforms to separate folders. From here, you'll need to make edits to the texture by creating layers above it. As far as ped texturing goes, it can be quite tricky, because its difficult to work out where the curves of the ped lay and so on.
Once you've made the edits you want (and its better to do this with small changes and often), replace the texture in OpenIV and load up the ped model using the YDR file. You can take a look at what you've changed and whether you need to make any further edits.
When you're done, you can take the textures in your folders, place them into a ZIP and release it as a texture pack (remember not to include the models themselves without proper permission from the model-maker.
If you've ever done any vehicle texturing, its a similar process.