Basics	It does not mean that you just swing the sticks toward the cymbal. You often need stick work of quick "simulative blow". There is also a shot that you swing fully according to the volume or the next movement.
Crash From Back	This technique is useful when you make successive shots with quick movement. I do not recommend this so much because cymbals can be damaged when you hit the cymbal at a bad angle.
Movement Shot	This is related to overall drum set, but when it comes to crash cymbal, movement shot becomes especially important. Relax your shoulders, Getting rid of useless movement of head, Get ready for the next movement or memorize the next location, Make natural flow by doing up and down strokes, Try to bend your arms and do not lose the balance of your body.
Practice	This is not limited to crash cymbal and is applicable to whole drum practice, but how about doing some exercise of swinging your sticks as a warm-up? I call this exercise "shadow drumming". You practice in silence only by a stick while assuming the position of each musical instrument, rebounding, and tone. This can be said as a image training. I guess this is the most common way of practicing because of the environmental reasons. This training does not match the real practice, but would be better than hitting a funny substitue.