Are you good at Call of duty 4?

COD 4 is a good game. Are you good at it?

1 When you have a M82 Barret.50 caliber sniper rifle ,what should you do?
2 An enemy is in front you but they don't know your there. What do you do?
3 You have an air-strike capability in a Hardcore team death-match, what do you do?
4 When sniping, what perk should you have?
5 When should you fire from the hip?