After breathing, there is probably no ability more essential than mask clearing. Though other skills, like gear assembly, are a necessary aspect of getting into the water, they technically could possibly be carried out by other individuals (although this is not recommended). Mask clearing, though, is a solitary skill, with the inabiility to execute it will instantly ruin a dive.
Mask clearing may be divided into three basic steps:
To start, position your left hand (fingers or heel) at the top portion of your mask frame to keep it securely against the forehead. Many divers use both hands, however this is unnecessary, therefore, I would suggest practicing with a single hand to limit movement.
Get ready to look little bit upwards by tilting your own head.
Initiate exhaling from your nose till the water is removed. When you start exhaling, continue looking up in order to get rid of all traces of water.