Being a former Windows user I always used to bit “Windows+L” to lock my machine when I left it – even for a short time.
On a Mac there are a few ways you can do something similar – my favorite is the following:
1. System Preferences > Security
2. Tick the “Require password to wake this computer from sleep or screensaver”
3. System Preferences > Dashboard & Exposé
4. In Active Screen Corners choose ex lower left corner and select “Start Screen Saver”
To lock your machine – simply move your mouse to the lower left-hand corner.
