You may add an additional unit to your standard unit (Zerglings), e. g. Hydras. This means you can try to play a solid opening (BO = Build Order), like HatchFirst. Zanster played 12Pool without Gas in Master. The community provided a Replay-Pack for it.

The video shows Railgan (GM), who executes a solid BO in ZvP. The mosten important difference between improvised Zerg-BOs in lower leagues and solid BOs in higher leagues is the Drone count after 4 or 5 minutes.