Not necessarily an exercise, but work on your hook grip! When the Snatch starts to get heavy you will be happy that you are able to hold onto that bar with confidence.
I would also look in the Snatch variations to help you improve your form and strength in certain areas. Don't neglect the squat!
Class I Total @ 198: 525/335/600 (1460)
"No citizen has the right to be an amateur in the matter of physical training.... What a disgrace it is for a man to grow old without ever seeing the beauty and strength of which his body is capable."