Using touring cars, try to use the 4wd ones as often as possible. Not hard as 1/2 the TC's ARE 4wd anyway.
As long as you tune it using a Torque Split between 40/60 - to - 50/50, your car should have an advantage on the standing start jump.(Thats one trick that will work.)
That, and make sure your first 2 gears have the power they "need" on the slider, using the 'all the way left on the first gear' method usually is very bad for standing starts. (Thats two.)
Drop your camber to zero/zero if its not already, try that. (Three)
Try to have sufficient weight planted over your drive tires. [The rear of car on MR, RR, FR] This is not always 100% possible without destroying the handling, but try to whenever possible. (Four)
Thats 4 things without knowing anything about your specific car and current tune on it. Anything deeper then this will require more specific information.
The only thing to really keep in mind, is these are standing start and low-gear-Torque tips, you need to be careful how much you change your tune simply for the first 20 feet of a multi-mile race. You might accidentally detune your handling everywhere else if your not watching close.
Best advice: change 1 setting at a time and try it out, better yet, copy your settings to the B or C setting slot, so you don't lose your initial tune if you don't like how things are heading.
