Torque is not your friend... and the P51 has plenty of it.
As per training, add a little right rudder trim before takeoff.
The way I go is to gently apply power and maintain a little back pressure on the stick keeping the tail wheel locked until rudder bites in, then stick back to center, and the tail raise, all along I apply power progressively. Tiny rudder corrections along. Once the tail is up, the plane then lifts off more or less by itself if enough power. can't remember numbers right now but I never go full throttle, not necessary I think. Well, at least not with a light load.
Slight aileron input to keep wings level, gentle climb, gear up and off you go until it's time to trim for level flight at cruising speed.
"Major Burns isn't saying much of anything, Sir. I think he's formulating the answer..." - Radar - M*A*S*H