Run in Zoo Guest Mode:
Hold the cursor forward and the Left mouse button to run.

Free Zoo Mode Extras:
At the start of a game in any Zoo mode (Challenge, Campaign or Freeform) Left click items you want like trees, flower beds, benches, etc. And move them to where you want them. Doing this saves money when you are on a tight budget.

Increase Starting Money in Challenge Mode:
Place the pointer over the 'Up' button that increases your money but do not click it then by pressing the 'Up' key on the keyboard your money will increase twice as fast.

Recycle Bins:
You have to pick up recycle bin trash yourself as Maintenance workers do not do it.