Zoom climbing is a good way to maintain an energy advantage. If you are above an enemy, you have an altitude advantage, and if you are at a decent speed, you likely have an energy advantage as well. Not always, because a lower plane could be faster than the higher plane, and actually have the energy advantage. That's not really the norm though.
If you have an alt/energy advantage, you will generally need to dive down on your enemy to gain the angles advantage needed for your shot. So you are turning an energy advantage into a positional or angles advantage. After your shot, or when you lose your window for making the shot, most pilots will "zoom" back up to regain the energy advantage, and try again. So you're are turning an energy advantage into an angles advantage, and then transitioning it back into an energy advantage again. This is basic BnZ or "boom" and "zoom" flying. The "boom" being the dive, and the "zoom" being the climb. Done correctly, you will end up high again, at nearly the starting altitude, with nearly the starting speed. Avoid the black out at the bottom, as this is a sign you are scrubbing energy. You can repeat this attack until you are successful, or until you squander you're E advantage and need to "extend" or die.
Most people squander the alt/speed advantage they have, and then die as a result. It's not always bad to dump the energy, but if you fail to turn it into a successful angles advantage and make a killing hit, you've given up your advantage and will need to finish the fight on even ground, or even from a disadvantaged state.
The three ways people inadvertantly destroy their energy advantage are by turning too hard, turning flat, or flying level for too long, generally while chasing the enemy plane. Turning too hard is pretty obvious. Turning flat causes you to loss speed, with no way to recover that speed other than diving, hence you will be lower/slower than when you started.
Flying level at the bottom of your "boom" is a more subtle way to kill your "E". Each plane has a top speed at a given altitude. That is the speed where thrust=drag. If your top speed is 350 at 10k, and you start at 15k at 375, when you dive to 10k you will be above your top speed. If you stay level at 10k, you will eventually slow down until you are flying at 350, even if you are WEPed at full throttle. You will be lower and have lower potential energy as a result. Not always bad, but not always good.
TnB fighting is generally slower, often at low alt, and is almost a race to get slower than the other guy, so he will be forced out in front of you to be shot. Obviously scrubbing too much E is fatal though. The pilot/plane who can maintain control at a slow enough speed to stay behind his opponent, but with enough speed to keep him from getting away, will usually win.
Somewhere between BnZ and TnB fighting is where Energy or "E" fighting resides. It is a mix of the the two styles, and in my opinion the most efficient way to score consistant kills. The way I look at E fighting is similar to a rollercoaster. In a rollercoaster there is an initial climb to gain energy, and then a series of manuevers designed to minimize energy loss, but maximize the "fun". Fast rolls, loops, etc, but low G's, and always with frequent trips back upwards to avoid flat turns and the resulting energy loss.
This is a pretty basic description, and not the only way to fight. Just an idea of some of the things the successful pilots know intuitively, and are constantly considering.
In a corsair, true TnB fighting is tough. With proper flap usage and throttle control you can surprise lots of the better known "turn-fighters" though. Some do it better than others, but the Hogs are not great accelerators. So even if you win the fight, it is easy to lose to the next red guy to come along. It takes time to rebuild your speed and/or alt again. Very good SA is needed to be successful here.
True BnZ fighting is tough too, but safer. It is hard to turn a large speed/alt advantage into a good angles shot, especially if the lower/slower guy knows how to deal with you. Your shots will be brief too, because your closure speed is so high. Assist city! It's also more boring than most floks want to deal with. It is safe though because a higher faster plane can stay out of the lower guy's sights.
E fighting kind of gives you the best of both worlds. The cosair is fast enough to get away from the planes it can't out-turn, and can turn well enough to out-turn the planes it can't get away from.
MtnMan