If you're talking about start up, a good rule of thumb is to close the needle valve all the way, and open the 1 1/2 turns to start the motor.
Then play around with the adjustment to get the best results. If it runs smooth, but not very long, it's most likely lean, and you want to turn the needle open (or couterclockwise).
If it runs rough and takes a little while to die, you want to go the other way. Playing around back and forth should allow you to tune it in.