Well, then just give it a few tries. Read the
tutorials carefully, then play a bit around with the different
programs and after that choose which ones you're going to use. If you want to make models only for you, you can try everything, but if you want to make models for the Hive that get approved and used, they must have certain qualities. I'd recommend you therefor to start with attachments, especially weapons like maces, swords, daggers and maybe polearms.
They're much easier and inanimate, i.e. they don't need to be animated. Trust me, with the time and enough private practice you will learn too how to make your own nice stuff and you'll also develope your own style, which will kinda be your signature.
The secret is just to try it out and not to be discouraged if a model gets rejected. It will take some time untill you make your first one that will be approved. The secret is only a combination of practice (i.e. modelling skills), innovation, creativity and patience.