Wear a PFD
Get a set of Grundins. (Grundins are rain gear if your not familiar with them)
STAY IN THE BOAT!!
Seriously --- Dress in layers since the weather can be finicky. I've fished the ocean in January and been wearing a tee-shirt and a flannel shirt and been more then warm. Other days, You never thaw out. Get a fleece lined hooded sweatshirt, warm gloves that aren't real thickly padded, waterproof boots and coat and pants that the wind won't cut thru.
If your going out on a boat, make sure you file float plan or someone knows where to look for you if you don't return when expected. Try to pair up with another boat that's going to fish the same area. That way if either of you have a problem, help is close by. This is assuming that you keep your radio/antenna in good working condition.