Don't run the car until have broken in the engine. This usually requires that you start the motor and let it idle for about one to two tanks. The manual should tell you what your high speed and low speed needle settings should be when you do this.
Once you got it broken in, you will have to run it at a rich setting which will make your motor bogg but spew a lot of fuel out the exhaust making a lot of smoke. This is a good thing because you're still breaking in the motor at this point. Do this for another tank or two. After that you can lean your mixture by turning your needle setting clockwise but only a little bit. Think of a clock dial and turn only one hour on the clock dial. Run it some more and gradually turn another hour and so on as you run more tanks of fuel. Eventually you will get to a point where the engine runs fast enough to engage the clutch quickly. Have a temp gauge with you to monitor your temps.
Do you have a 3 shoe clutch with three springs on it? Or do you have a cone shaped clutch bell and clutch shoe with one spring in the middle? Need that information before you can get any help on clutch tuning.
Also what fuel are you using? Make sure you use the fuel recommended by your instruction manual to start. Most likely it will be 20% nitro.