For me it depends on the situation. In large fights you want to try to stay fast and get above the fight. The Corsair holds on to airspeed very well, but if you get slow she doesn't regain speed or altitude easily. This can make her vulnerable in large furballs if you let your enemy drain you of E. In small fights or 1v1 where you don't have to worry about the bad guy having friends show up you can afford to slow down against most opponents. However against Zeros, I-16s, Brewsters, F4Fs, Hurricanes, Ki-84s and I would also add early-mark Spits (I and V) and 109s (E, F, and G-2/6) you want to stay fast.
Some guys advocate getting your flaps out as early and as full as possible and leaving them there for the duration, but I disagree. I try not to let the fight get slower than the 200-250mph range (1-2 notches of flaps) if I can. Drop a notch of flaps only as long as you need it (IE, going through the top of a vertical extension) and get them back up immediately. This is the REAL key to flaps in the Corsair: You're going to be constantly working them up and down throughout the fight. The rudder is also VERY important to effective handling of the Corsair. She has one of the best rudders in the game, so you want to use it. I'm almost constantly leaning on the rudder when maneuvering in the Corsair, especially in High-Yo's and other vertical maneuvers.
Corsairs excel at the rolling scissors, and in general any other contest involving roll, especially at high speeds. At low speeds she doesn't roll quite as well to the right, however the resistance going to the right isn't as significant as aircraft like the 109s. She'll hold together at dives nearing 600mph, and doesn't really begin suffering control lock until around 550mph.
As far as fuel management goes, I prefer taking off a base or two back when flying the F4U-1 and 1A and taking full fuel. I use this fuel burn procedure:
1. Left Wing to 50%
2. Right Wing to 75%
3. Left Wing to 25%
4. Right Wing to 50%
5. Main until empty
This provides you with an excellent reserve if your main tank gets holed (fuel and engine oil seem to ALWAYS be the first two things to get hit in the Corsair....) and can help stabilize the aircraft against torque. In the Mains you can go to 1/8 Left, 1/4 Right if you want to lighten her up further, but you won't have as much of a reserve (you can get her about a sector on cruise settings with that). I usually fly the 1D/C for ground attack so generally take full ordinance and no DT. In the -4 I'll go without tanks if I'm scrambling for short-range defense, but if I have time for climb out I'll usually take 1-2 DTs.