F4Us particularly are good planes for skids. They have one of the most effective rudders of any ship in the game, and unlike most of the stable retain rudder authority even at high airspeeds (in most planes, the rudder is only useful at low speeds to BEGIN with, making skids and slips to dump E rather pointless).
Also, there's two entirely different maneuvers here.
A skid uses rudder by itself. The effect is sort of like "drifting" a car. The plane more or less maintains a steady course, however its nose is swung around on an angle. It does scrub E, however its MOST effective use is for getting a guns solution on a target that's JUST off angle. I've gotten quite a few kills on guys who probably never expected it because they were off to one side and out of position (especially front-quarter passes where he's off to the side to prevent a HO) by kicking the rudder and hauling the nose over and bringing him in line with my guns (be advised, though, that rudder can do some odd things to your bullet stream). It takes timing, practice, and luck, but a skid at just the right time can get you a guns solution or snapshot that would be impossible using other ACM.
Slips are something different, and are NOT the uber-maneuvers you make them out to be. It's basically a one-shot trick, and honestly it's not so much the overshoot in of itself, but rather the plane is effectively turning in the OPPOSITE direction of the bank (in a slip, you apply roll opposite to the direction you're ruddering: left roll/right rudder, right roll/left rudder. The plane banks one way, but slides in the opposite). It's a deception maneuver that against an inexperienced pilot can fool them into breaking the wrong direction, either letting you escape a guns solution, or getting you on their six when they run past. However if the target doesn't bite, you're in a very predictable position.
To be effective, a slip in one direction should be followed by a skid in the OPPOSITE direction.
Really, though, the best time for a slip is to shed airspeed if you're coming in too hot on landing. Most experienced pilot won't fall for this even ONCE.
