Attacking and Defending Skills in Volleyball

ATTACKING

Serving: Contact through the centre of the ball with an open hand following your arm through throwing the ball straight up above your head and having contact whilst it's still above you. 
Drill: yourself +1 ball. practise the action against the wall catching your rebound and repeating.

Digging: Wrists together and hands overlapping, arms straight pointing downwards at about 45 degrees slightly away from chest. Ball having contact with forearms and forearms come up spiking the ball to a setter.
Drill: +2 players. 1 player sets the ball for the other and the swap practising setting and digging in a game.

Setting: Hands up above head early ready for the ball, fingers and thumbs in a triangle shape and making a pinching movement to set the ball for a spiker. Extending the arms will allow more height. 
Drill: yourself +1 ball. Set the ball to yourself then start moving whilst setting.

Spike: Jumping into the set ball, one arm above head and doing the same action as a serve. The arm must be finished lower and the ball is aimed to hit the ground.
Drill: team +4 balls. With the team, have 2 setters on each side of the net with the other players lined up behind with the ball. The ball is thrown to the setter, setting the ball and the player is able to complete a spike over the net. 

DEFENDING 

Blocking: Front 3 in row move close to the net and have their arms above their head straight to block view of their server to the opposing team and during a game to block a spike. 
Drill: +3 players and 1 ball. Have 3 players blocking and the other 2 players setting and spiking.

Diving/Sliding/Rolling: Diving, sliding or rolling to save the ball from hitting the ground. Keeping arms extended to hit the ball back into play. This is normally used after a spike has been competed from the opposing team. 
Drill: practise diving in and landing in the correct way on a mat, then add a ball in simply thrown and left to last minute before diving. Once this has been practised then one player spikes and the other player can dive saving that spike.