First of all turn the bass all the way down and the highs most of the way up. This will instantly make your scratching sound more professional.
Basic scratches:
The scribble - move the record backwards and forwards without adjusting the crossfader. Faster you move it the higher the pitch will be obviously.
The Echo - Perform the "scribble" with a repeated sequence of movements, pull the line fader down to give the impression that the sound is fading off into the distance. Experiment with letting it fade out then slamming it back in for various effects.
"THE CRAB" This is one of the most difficult yet most essential techniques to master if ya wanna get into scratching. easiest to start with the classic "aaaaaaaaaahhhhhhhhhh" hip hop sample IMO
for the purposes of this excercise we will number the fingers on your crossfader hand. 1 being your pointing finger 4 being your little finger.
place the crossfader between your thumb and 3rd finger. As you apply pressure towards your thumb with your 3rd finger, let it slide off the crossfader. When it slides off (the motion is very similar to snapping your fingers) your 2nd finger will catch the crossfader, apply pressure with it and let it slide off then your first finger will catch the crossfader. Repeat with first finger. Do this very slowly until you get the idea. Your thumb is basically a return spring. DO NOT APPLY PRESSURE WITH YOUR THUMB. It will return all on its own. This is the secret to crabbing. The whole process requires a VERY LIGHT TOUCH.
With your other hand, simply move the record very slowly in one direction (for one full crab cycle with the other hand) and then slowly back the other direction. Variations in the push pull speed will alter the pitch of the sample allowing you to play the sample as an instrument. Often when crabbing you simply let the sample play and use the crossfader crabbing action to get the triplet effect. Usually I let it play forward for one crab cycle of the other hand and then pull it back for another cycle. This is how hip hop guys get that "ah ah ah ee ee ee" (if that makes sense) thing going on.
there are dozens more techniques and whole books of scratches. One guy has even created a scratching tablature so that different scratching techniques can be notated.
Master the basics first!!!
Hope that helps