play around with different mand possitions on the record!! tips to begin with are easy if you put your finger nearer the outside of the record, bend your elbow more!! get closer to the deck, position your elbow closer to the horizontal of the deck, and you can get the motion of locking your elbow, just getting say a 10 degees jurk motion to acunplish the tip!! this also helps with scribbles, after a while, as your fore arms become stronger in the scratching muscles and you have better control, you will find that you will be able to do them in your natural posture!!
alot of people get all ridgid when they scratch, which limits you in al fairness, move around with the different tecnniques and you will find that some of the ones you initially found hard, easyer to flow off in a routine!!