Snake. I love to steal the bag from another players square when they least expect it. Snaking requires you to be lightning quick and incredibly precise. Like most other trick shots, you also have to know when to use it. Snaking all the time will make you predictable. I like to pick off passes with a variety of moves (axe kick/sole shoves, high round kick & side kicks, flying knees, and flappers), generally when the bag is eye level and before most players get to them. Picking off passes high usually lets you avoid contact calls since you will be in their square, unless of course they like to steal high passes too or like to use headbutts.
Players that play too close to the line and/or kick a lot before passing are very easy targets. A very quick toe kick to try and flip it above and behind them or kicking it to their weak side works well. Or you can sole shove to their face or chest to mess up their rhythm. Be carefull not to spike it. As a king, this can be very usefull because you can snake after the player receives your serve. Or if nothing else use it to keep the bag away from a player that can threaten your reign and set yourself up for a better shot. If the defending player tends to kick only once you can target a straight pass to their chest and wait for them to play it. As it bounces off, snake the pass with a quick to kick to their weekside. Even better if you can manage to kick it straight up and make the defender blink. It's funny to see them frantically search for the bag above them afterwards.
Snaking a serve intended for another player is a great way to surprise the king. Kick the serve right after it leaves the king's hand to try and sail it behind him. This works just as well if you snake the serve and pop it behind the person it was intended to. This is generally used to remove a player with a high score and the King is not a threat to win from the point you just gave him.
Players with their back turned to you can be great targets as well, provided they are in your range and the footbag is to their side or otherwise easliy accessible. Same basic plan, you want to surprise them and kick the bag to an open area in their square or to their weakside. I've gotten a few sole shove snakes within inches of a bunch of local players faces from this! The intimidation factor is great
After a few good snakes you can start to fake the move in hopes of baiting players to defend/adjust and throw them off. It can be enough to make an inexperienced kicker lose their concentration and miss the bag.
) and I did a quick low right inside kick sending the bag to the right, immediately followed by a kick made with the side of the knee, that hit the bag while it was still going up and changing its direction to the left. So like a one legged inside-knee double tap 
Start a pendulum and while your target of choice is looking over your shoulder waiting for the bag to come up and over you, reverse your pendulum behind your back and bring your foot forwards to launch the footbag at your oppenent's croch. This is a devistating kill that can easily send your friends to the floor. The faster you do it the better it works and hurts. 
Bane of my existence 
This is probably one of the more frustrating shots to defend. Peter is one of the kids from Lane. Terrible player. Bad mechanics. Lazy attitude on the court. How the hell does he have his own shot, you ask? Well, it's not a shot of his own invention, it came about when others started mocking his kicking style and finding that they could score just about every time it was used.