There's a trick I use with this shot and with its difficult cousin, the one where you have to make a long backwards cut into the corner.
Stand behind the OB and line up as if you wanted to shoot it directly into the pocket. It's not enough to just stand behind the shot and eyeball it, you want to actually line up with your cue stick and pretend like you're gonna strike it. Let the cue stick come very close to the OB and imagine touching it with the tip (in whatever place that would send it into the heart of the pocket). Now imagine that after touching that place, the tip left a little chalk on the OB. Stare at that imaginary chalk dot like your life depended on it. It helps if there's a little nick or scratch near where the dot should be. If there isn't, it can help to use the number or the stripe or something.
Walk back around to your cueball and as you walk, keep your eyes on the spot, don't even take your eyes off to walk properly =). If possible, try to line up on the cueball using peripheral vision only and keep staring at the dot.
Finally, imagine the back side of the cueball contacting that dot perfectly as you shoot. And do what Russ advised, using a touch of outside english if it's possible to get shape that way. It really has worked for me, and I find it works especially well on these cuts because you can more easily imagine the backside of the cue ball from these angles.