hi
the first thing to check would be to make sure your swash plates moves in all the right directions.
when tail facing you the swash plate should tilt to the left when you move the stick to the left and vice versa
then it should tilt foward when you move the stick upwards.
after this place your thrtlle stick at half and see if your swash plate is square if not the best way to achieve all this is to set all trims to centre disconect all ball links to the swash put both sticks from the radio at half, reinstal servo arms so they are 90 deg ,place swash plate to it midle of travel and conect links by adjusting lenghts.if all is 90 deg and centre your swash plate should move up and down without tilting to either side.
it is however normal for the heli to want to drift left a litle you can cheat this by triming it so it barely does it but it will always drift,it is caused by the main rotors centrifuge force.
next will be the tail rotor the helis nose is what you direct if you give left the tail will go right to make sure you have this corecly
look at the leading edge of the blades the direction it moves to is the way it will pull or push the tail if not cerect just reverse servo.
the gyro can also be reversed an aesy way to check it
give left command and see in what direction the servo moves then grab the tail and give it small jerks to the right and look at the servo arm it should corect by giving left command.
i know i gave you more info then requested but want you to have a good experiences i've seen to many guys try with all servos reversed not prety they usualy fix it and sell it at the LHS and i get to set them up for the new guy once sold.
anny other question you may have just ask
steff