I have posted several things about wrist locks during the past year and a half (see here, here, here, here, here, and here). There are a few noteworthy features of the wrist lock in my experience: (a) they are wickedly sneaky and effective and can be set up from a number of different positions, (b) when training partners get caught in them, they often act like you've somehow cheated or engaged in mere "suburban techniques" (to use the derisive term the Gracies used for leg locks back in the day), and (c) as a general rule, people don't take them nearly as seriously as they should. For these and related reasons, you should add them to your game! Why? Because to the extent that people dismiss them out of hand (no pun intended), this means that they're not spending sufficient time learning how to prevent and avoid them. In this respect, like leg locks, wrist locks can be short cuts to victory against the unsuspecting.
You just have to be prepared for some grumbling from your partners when they leave the door open to have their wrist locked down! For whatever reason, your successes will be discounted. Perhaps it's a misplaced fealty to tradition or simply a misunderstanding of the savagery of wrist locks. Either way, just know in advance that you might get some dirty looks however silly and unjustified this attitude happens to be. That said, Keenan Cornelius just released a video which shows several set ups (see below). I also found a video by 7th degree coral belt Fabio Santos--which I included as a reminder that wristlocks are actually "old school" no matter what your training partners might suggest! My only caution: Be careful when applying wrist locks. They are more effective than they seem at first. Like some leg locks, caution is the key. That said, watch, learn, and go train!