Advanced nunchaku techniques take time and effort to learn. They can be grouped into several categories:
Locks and chokes
Twirls
Longer sequences of flowing strikes
More advanced gathers
Knowing the strengths and weaknesses of the nunchaku
Ultimately I intend to consider each of these categories separately. You'll have to wait until I have time to expand this into a proper section but for the time being here are some things to think about:
It's all very well swinging nunchaku around your body at high speed but due to their very nature (two sticks connected by a cord) they also make ideal choking instruments. One advanced nunchaku skill is to be able to use basic locks and choking techniques using nunchaku. This is an area that is often well covered in discussions of police nunchaku as such techniques can be used in a more measured fashion than nunchaku strikes.
As well as simply passing the nunchaku from hand to hand another advanced nunchaku skill is to be able to change your grip on the nunchaku using just one hand. This is mediated by "twirling" the nunchaku in your hand, by letting go of one end, allowing the nunchaku to pass across the back of your hand and then catching the other end. It's a technique that requires a good amount of practice before it can be done reliably. Don't try this one near anything breakable! I can personally guarantee that the nunchaku will fly out of your hand and destroy the most valuable item in the room!!!
A very simple extension of basic nunchaku technique to advanced nunchaku technique is to develop the individual moves described in the basic section into flowing combinations of strikes. The kind of combinations that you want to try are sequences of moves found in nunchaku kata (pattern). In general the principle is to allow for multiple chances to hit your target in a sequence of flowing movements.
Advanced gathers are an intrinsic part of advanced nunchaku technique. As you may have observed, when you hit something with nunchaku the free end has a tendency to fly off out of control. You don't want to just keep swinging if that happens because the swings will be out of control and could well end up trying to go through your own head. Ouch!!! Instead you need to gather the nunchaku back up into a controlled position. It is possible to gather using your feet, legs, shoulders and even neck in addition to the basic body gather described in the basic technique section.
To become really skilled with the nunchaku you need to understand their strengths and weaknesses. Nunchaku strengths include incredible speed and a great deal of flexibility in what can be done. Nunchaku weaknesses include difficulty in blocking (compare with Tonfa for instance) and the need to recover after striking. If you fully understand the weaknesses of nunchaku then you will be in a better position to overcome them.