Lotsa good CTS exercises on the Web, including the one described by Mali, which I've been using.
A "hand shake" is great. Not shaking somebody's hand in the usual way, that is. Instead, hang your hands down at your side, bend the elbows about 40 degrees, and shake the hands like you're shaking them dry. When you get it just right, you can feel the blood pooling in your fingers. It feels great.
Also--and I have no idea whatsoever why this one works--make a fist with your thumb inside instead of outside. That is, bend your fingers over your thumb and hold it for 15-20 seconds. Not too easy/not too hard: Just right, like Momma Bear's porridge. Then straighten out the fingers of the hand like you're gonna salute the Sergeant Major.
Some exercises are called "nerve gliding", whatever that is. Lots of them. Try a wide variety and see what works for you.
And keep that wrist off the hard desktop surface when you use your mouse. A soft gel pad under the forearm works nicely. And take breaks. And shake your hands every 20-25 minutes.
Oh, Yes: Keep on Shooting.