The Corsair is a relatively tricky plane for the newer folk. Once you fly it for a few tours, you get used to it. It sports good turn, zoom climb, roll rate, and dive abilities. But there are many other aircraft that are significantly more difficult to master. P-38 is one of several. I have flown the 38 for over a year and I still get my arse handed to me nearly every time I fly. But that doesn't help that I fly straight into the furballs like a fool.
I think the majority of the AH community will tell you that the best planes to learn to start flying in are the Spitfires, Hurricanes, and perhaps Ki84 and N1K. I personally wouldn't spend too much time learning the "easy-mode" planes once you get the hang of the game.
If you really want to become a very good stick, you will need to challenge yourself. Flying planes like the 109, P-47, P-38, P-40s, Mosquito and other bigger, and heavier, aircraft will help you expand your understanding of ACM (aerial combat manuevers). You also have the AH Training Staff at your disposal. They are a great help in teaching you the fundamentals of ACM and how to get the most out of your plane. Also don't hesitate to run to the DA and ask some folk for some 1v1s. They are also good learning resources.