Q1.
As a player weaves into the penalty box a chasing defender tries to trip him. Although he stumbles the attacker manages to get his shot away - but its weaker than it should of been and the goalkeeper easily saves it. The attacker demands a penalty. What now?

Answer.
Attempting to trip an opponent is an offense, whether it succeeds or not. If the striker had managed to score then clearly you could have played advantage, but as it is you need to intervene. Award the penalty and, if you judge that the attempted trip clearly denied an obvious goalscoring opportunity, then issue a red card too.

Q2.
A striker races into the penalty area and takes a theatrical dive to evade a reckless tackle by a defender. No conduct was made. Both are on a  yellow card. What do you do?

Answer.
Send the defender off – a second yellow, then a red. He clearly attempted to trip the attacker with a reckless challenge. Restart the game with a penalty for the attempted trip: it doesn't matter that no contact was made. In this situation, you cannot also punish the attacker for simulation, as, had he not dived out of the way, he could have been seriously hurt.

Q3.
A defender deliberately trips an opponent near the centre circle to break up a promising attack. Its clearly a foul but do you show a card? If yes what colour?

Answer
This is not a clear goalscoring opportunity so its not a red card but it is a tactical foul so you must show him a yellow card for unsporting behaviour.