Set up two low verticals in your ring, one at 3:00 o'clock and the other at 9:00. Pick up a canter at either 12 or 6 and stay on a large circle until you have a nice, balanced quality canter going. Think rhythm, rhythm, rhythm. Once you have the nicest, most rhythmic canter going you can achieve, come off the circle and jump the nearest vertical. (Ideally the fences should be set up to where you are not presenting your horse to them while on the circle, but it's also not more than a few strides to come off the circle to the fence and disrupt the canter on approach. You do not want the jumps to appear as part of the circle or else all you will be training is the horse to run out) Ride straight after the fence, but then resume circling since it will most likely have fallen all apart over the fence. Lather, rinse, repeat until it all starts to flow. Be careful not to do anything different on the way to the fences. The idea of the exercise is to let the quality canter take care of everything else.
The other thing you can try it to set up a single fence on a large circle and this time, keep it as part of your actual circle. Again, it's all about a nice canter. The low vertical is just another canter stride. Do as little as possible. Use the exercise to try and figure out what you might be doing to send either mixed signals to your horse or un-needed aids. A lot of us ride with too much noise especially in our hands. Figure out how to ride as quietly as possible. This exercise usually produces some nice light bulb moments. It's my favorite one for when things start to go wrong and you don't know what you did to screw everything up.