Well, one of the important things is flow. A moc usually looks good when it is shaped well, that there is a clear design, so it doesn't look slapped together. Unless of course it is intentional.

It helps when there aren't too many holes and when the shapes are clearly defined.

Nothing else that I could give as advice though.

Well, I don't know what your mocs look like, so maybe you already do this and my advice is irrelevant, but...

The best advice I can give is this: Experiment. About a third I'd say of the time I spend making a moc is spent flipping between armor choice A versus armor choice B. And then I see what a C D and F would look like. Then I settle on A. Then I switch to B later- Like that.

Got a long upper limb piece? Do you want Inika leg, Inika shoulder, Piraka leg, or Metru leg armor? Or how about Gali M. or Kalmah or Takadox armor? What about colour? And what if you start building it custom?

So really, just try everything you can think of until you find something you really like. Also, have the perseverance to keep hunting until you find the exact part you want- which I'd say is another third of my average mocing time.

Piraka/Inika/Mahri/Phankuta torsos are not your friend.

Unless you can hide them within the MOC, don't ever use them in their intended role.

DON'T STRESS OUT AND GET FRUSTRATED. Plus, go buy tons of bulk Bionicle parts from *Not saying website*. Of course, I have no talent whatsoever in this field, too, but keep practicing. That's what I did, and I actually did start to get better, even with the pathetic amount of pieces I have.