Assistance work is often overlooked by many of us however, it should be reconsidered for many reasons. Some assistance work will help prevent, treat, or rehabilitate injuries, whole others will help strengthen weaknesses in specific areas to improve the larger lifts and skills and improve your big picture fitness. Getting in some good volume without regards to intensity with these exercise will really show great results. Here is some assistance work for the hamstring that will help with strength in the bottom of the squat, increase the dead lift, as well as all of the Olympic lifts.
Straight Leg Deadlift- 5x10-12
GHD Hamstring raises - 5x5
Good Mornings 3x20-25