Firstly i wanna show you simply technique ,it's really useful not only in dojo but also on street ,so:
A) grab opponent in natural position.(one hand grab arm ,second on collar/shirt next to shoulder)
B) Trading on the fingers of the left foot from slipping right leg and hip at the enemy, while pulling on his right sleeve or wrist (in the same direction you push the left shoulder) and right leg blocking the lower leg.
C) The left hand pulls the opponent's sleeve/wrist diagonally down and locking leg while we raise it upwards.
D) opponent lying on the ground, and this position offers many possibilities of locks and grabs.
***It's good to provoke opponent to be moved forward and right.
and the film to visualize it: http://www.youtube.com/v/4IpweRu1KB0&hl=en