Ok, here you go. This is how I do it.
First of all, there are two methods that work well. 1: Use autopilot (shift-X), this will work, but IMO it's the boring way to do it.

2: Don't mess with the flaps or trim. (Unless you are very heavily loaded, then a notch or two helps a little.)
Start engine, go to about 50% throttle. Try to use right rudder (pedals or twist stick are best) to keep the torque from putting you into a continuous left circle. Slowly increase throttle to 100% while continuing to use rudder to maintain a straight run down the runway. Try to keep the tail on the ground as long as you can. At ~160 mph pull up gently, lift off, and retract gear before you break them off. After this I usually use auto pilot and WEP to let the computer reset my trim and do a maximum angle climbout. (If you are using the F4u, the best method is very slow throttle ups while applying rudder.) Once you get the hang of it, you can take off by going to WEP right after startup and rocketing off the tarmac. The key is the rudder, without it, all but bombers and the spitfire are VERY difficult to lift off. (There are also rudder keys on the keyboard, but they are more difficult to use. "a,s,d" are the default rudder keys.)
Hope this helps.