Always work symmetrically
The key for designing incredibly fast is working symmetrically. You’ll be designing as you go, but because you’re working on both halves of your character at the same time, you’re creating harmonious rhythms. Ninety nine per cent of all creatures on Earth are symmetrical, so working this way helps you tap into this basic concept. Also in ZBrush, once you move off symmetry it’s very difficult to reconfigure your character to get symmetry back. Always save your T-posed characters before you begin posing. You’ll no doubt want to return to that T-pose version for revisions at some point.