THE TWO MOST IMPORTANT THINGS IN GRAPPLING - YOUR GRIP AND YOUR CORE.
Check out Chad Howse and his challenge workout that will undoubtedly work everyone's grip and core. On occasion people will ask me what they can do off the mats to help improve elements of their grappling game. My response is usually not as exciting as they would hope, but, by far, the most important attributes you could improve are core and grip strength. Just think of it this way, the stronger your core and grip are the more dynamic your movements will be you won't have to worry about getting numb hands from holding the lapel or getting stuck flat on your back when you get tired. Do I really need to say more?
So get your ass up off the couch and work that grip and core.