I can't remember which way the rudder goes, I just keep moving it so the plane tracks straight.

If you have a tailwheel then you can hold up elevator to hold the wheel in contact with the ground to help steering. As speed builds up you need to remove the up elevator and allow the tail to rise. A little up at this point will get you airborne.

If the model is really poweful then elevator contol isn't quite so critical (the engine will accelerate the aircraft more quickly so rudder will become effective earlier and the tail can therefore rise earlier) but rudder is tricky. If the model is low on power then rudder should be easier but you may need to play with the elevator a bit more.

I would open the throttle slowly at first until you get used to it.

When applying rudder during take off you need to add a bit then wait. If you try and 'fight' the model on take off it will fish tail with the possibilty of ground looping. It not that hard once you've had a couple of goes though.