Okay, so you've made sure the runway is clear and now are in position for takeoff. If you are in a tail dragger (conventional) aircraft (most WW2 fighters have the tailwheel) then lock your tailwheel. This will help in keeping you tracking straight on the runway.

If the aircraft has it, lower your flaps to takeoff position. Start applying throttle. DO NOT GO FULL THROTTLE RIGHT AWAY! Roll into the throttle (apply a little, then a little more) until you are at full throttle. This will help with torque steer that all aircraft have, some have it worse than others. This is where you apply throttle and the aircraft wants to turn one direction. Different aircraft's propellers spin different directions, you'll know which way it'll want to pull once you start applying throttle. To offset this, apply a little opposite rudder. This is a "feel" type deal. Too much and you'll steer hard one direction, too little and it won't help. So feel for it.

As you keep applying more throttle and airspeed comes up the tail will start to come up. Do not pull up yet. If you've done everything right the aircraft (unless heavily loaded) will lift off nearly on its own. Once you are airborne, pull up your gear and slowly bring up your flaps. Pick your heading, and settle into a nice climb out. Not too steep or you will stall. If you stall, just stop pulling back on the stick and let the plane sorta level out. It just needs more airspeed. Some aircraft climb better than others. You can study (google, or asking one of us) what the best climb speed is for your particular aircraft.

Some aircraft do not have takeoff flap settings (such as the Spitfire). You do not need it. Just follow the other steps and disregard the flap settings. Hope this helps.